Revised transfercase switch *READ THIS THREAD!

Post by **HenryJ** » Tue Jun 07, 2005 8:16 pm

THIS IS A MUST READ THREAD!

ZR2.com thread- NEW TRANSFER CASE VACCUM SWITCH

Unconfirmed at this point, on my part, but I'm going to look into it.

s10zr2 wrote:thought i would post this for the members that have not had the dreaded transfer case fluid sucked up the vaccum line, to the hvac controls, and runing everything in line problem! THE SWITCH HAS BEEN REVISED TO PREVENT THIS. new # is 89059420.

GM parts direct lists it for $19.95

Post by **HenryJ** » Wed Jun 08, 2005 2:28 pm

Checked with the dealer today. The new #89059420 supersedes the old number, so there should be no chance of getting the old part.
However if you look it up by application there is no mention of this part or the revised number.
This may mean that the dealers systems have not been updated yet.

My price at the dealer was $29, but I talked them into $25 for it. I want to change mine, just for the peace of mind.
I want to make darn sure that it was manufactured after the afore articles mentioned date of August 2004, that is one of the reasons that I ordered locally.
They did have one of the old part number switches in stock , so I will be able to compare the two as well.
Bob said that GM usually recalls inventory when there has been a revision like this. They haven't heard of one for this yet though. Be careful if you are having or have had repairs done recently. You may not have received updated parts.

ludwis · Post by **ludwis** » Wed Jun 08, 2005 3:15 pm

I had mine repaired a number of times. Its been working well for quite some time. Perhaps I should investigate having it swapped out before the warranty expires in 2/15/06.

What do you guys think?

Post by **HenryJ** » Wed Jun 08, 2005 3:33 pm

ludwis wrote:I had mine repaired a number of times... Perhaps I should investigate having it swapped out before the warranty expires in 2/15/06.

Do you have the repair order and a part number?
Is there a chance that you already have the redesigned part?

F9K9 · Post by **F9K9** » Wed Jun 08, 2005 3:48 pm

ludwis wrote:I had mine repaired a number of times. Its been working well for quite some time. Perhaps I should investigate having it swapped out before the warranty expires in 2/15/06.

What do you guys think?

I don't know but, the more I learn the more I worry

Under 10K and I am imagining all kinds of horror scenarios. I have noticed that I have air coming out the vents on most of the HVAC settings.

Might be already to late for me. Am certainly glad I made the decision for the extended warranty.

Post by **HenryJ** » Wed Jun 08, 2005 4:17 pm

f9k9 wrote:...Might be already to late for me...

Well at least check it out before lots of damage is done

I really shouldn't talk. I have been meaning to crawl underneath my truck and check mine since I said that I would in the HVAC thread.
It is just one of those things that seems like lots of work, when in reality it is not hard to do at all. You just have to do it.

I am going to be giving mine a thorough look before leaving on our expedition this Sunday, and the new switch is a really good excuse to just change it before problems arise.

This really is cheap insurance. $25 is less than many frivolous expenditures, and may prevent a costly repair in the future. This is one of those things that if you wait until you have a problem, it may be too late. When the system is contaminated they do replace the controls and slaves, but I doubt that they actually decon all the lines completely. These vacuum lines may not be compatable with the ATF, and who knows how long they will last after being subjected to the fluid?
Will they outlast the GM warranty?... Of course they will. If you don't plan to keep the vehicle long term , it may never be an issue. Heck who knows it may even make them last longer since they may not dry rot as they may have before?

I hope to negate all these worries, by changing the offending switch. I'll just chalk it up to one more preventative maintainance item.

AZS10Crew · Post by **AZS10Crew** » Wed Jun 08, 2005 7:17 pm

What's the HVAC problem caused by the fluid backup? Is it air coming out the vents like f9k9 mentioned? I've been getting that more and more lately but not bad enough to search for a fix.

Post by **HenryJ** » Wed Jun 08, 2005 7:29 pm

AZS10Crew wrote:What's the HVAC problem caused by the fluid backup?

HenryJ wrote:Watch for signs of transmission fluid. There have been cases of vacuum switch seal failures and fluid drawn in to the HVAC system causing damage.

i was right all along!! ( HVAC problem )

Hissing sound from HVAC

Dragonmaster wrote:
NTXCrew wrote:I just noticed a hissing sound from my HVAC control panel this morning on my way to work.... it was coming from the HVAC controls. When it's in vent mode (A/C, too...I think) - no hiss - works fine. When it's in heat or defog or combo modes, it still blows through the vents as well and MORE through the vents than where it's supposed to (based on the control setting). The different fan levels work and the Hot/Cold still works, too. What Gives????...
Mine did this before I sold it. Turned out the transfer cas vacuum switch was bad, and that caused the vacuum to draw t-case fluid into the havac control and kill it. The fix involved a new vacuum switch, removing and cleaning all of the vacuum lines, vacuum reservoir, new hvac control unit, new vacuum actuators for each different mode on the door controls, and about $1800 later it was fixed (out of warranty)...

Some of the other forums may document the symptoms better than we have here.

Best thing that you can do is reach up on top of the transfercase and take loose the vacuum line attachment connector from the switch to look for signs of ATF.

F9K9 · Post by **F9K9** » Wed Jun 08, 2005 9:27 pm

OK Brule, I know you are busy and getting ready for your trip but, if I can research scanner laws it's time for one of your infamous pictorials on where to look for this stuff ar

Post by **HenryJ** » Thu Jun 09, 2005 4:02 am

I'll take some pictures when I do the swap. The new switch should be here today so that I can compare them and confirm manufacture dates.

Stay tuned

F9K9 · Post by **F9K9** » Thu Jun 09, 2005 4:16 am

Thank you, Sir

Post by **HenryJ** » Thu Jun 09, 2005 3:31 pm

Ok people, this one is a MUST DO!
My truck is a 2001 and has just under 50,000 miles. My switch DID show signs of leakage. Not real bad, but it was there.

On to the information:

The new switch is part number 89059420 and has a blue inspection paint mark.
The old switch is part number 15664811 and has a green inspection paint mark. (see picture below)

You will need a 7/8" deep socket. I used a KAL tool 7/8" sender socket (see above image). It has a hex head for using a 13/16" wrench, much like some spark plug sockets. The wrench and socket worked the easiest for me.

Access with a 2" body lift is pretty good and did not require removal of the transfercase shield.

I was able to reach over the left side of the transfercase , Just above the ID tag. follow the triple vacuum hoses to the switch.

Just pull the hose connector loose from the switch.

In that photo you can see the reflection in the upper left hole from the ATF in the tube. Two out of three of them showed contamination.

Be sure to clean around the switch before removal. Use the socket to unscrew the old switch.
I reused the o-ring off of the old switch since it was in good shape, and pliable. If in doubt replace it.
The switches are straight threaded, and the rubber o-ring is the seal. No compound or thread sealer should be needed. Do not use teflon tape.

Start the new switch on the hole first , then slip the socket over it and tighten it. Snug is fine, don't get carried away.

Most of this is done by feel, since it is very hard to see up there. Pay attention to where the pin is on the switch. You will have to feel for it's position and reattach the hose connector correctly.

It is not too bad and only takes about 10 minutes to complete. It may take longer without a body lift since you may need to remove the transfercase shield to get enough room to work.

F9K9 · Post by **F9K9** » Thu Jun 09, 2005 3:40 pm

Excellent write up, HJ

Not nearly as scary as it first sounded

Is the socket required or would a box end wrench work? I know you have plenty of deep well sockets but, it sounds like no room for a rachet that required you to use that style socket.

Post by **HenryJ** » Thu Jun 09, 2005 4:07 pm

f9k9 wrote:...Is the socket required or would a box end wrench work?

I did not find a way to get a 7/8" wrench on it and have room to turn it.
I will say that I did not try it for long since I knew that I had a socket. It really might be worth add this to your tool selection.

Talking with Bob, this part has not been available for very long. He could not imagine that any of those who received warranty service , had the new part installed.
The part number should be on the warranty service repair invoice. If it lists the old number, you need to make a change.
Next check would be to see if you have the green paint on it. Careful inspection with a mirror or digital camera, may reveal the green , as in my pictures

I was not able to see the ATF until I removed the switch. It is way to hard to see into the lines from underneath. I would suggest removing it to check it. Heck , just cut to the chase and replace it.

F9K9 · Post by **F9K9** » Thu Jun 09, 2005 5:47 pm

Ordering mine now

Can you recall where you got the socket?

Top_Sgt........gimme one of your fabulous SAE/Metric conversions for 7/8"...maybe one of my miracle metric box end rachets will work.

Thanks once again for all your work, Brule.

I dislike getting air out my vents when on defrost

a2b · Post by **a2b** » Thu Jun 09, 2005 10:29 pm

so brule, what does the new switch do?

Post by **HenryJ** » Fri Jun 10, 2005 4:15 am

a2b wrote:so brule, what does the new switch do?

The seals in the old switches fail and allow the vacuum system to draw the ATF from the transfercase into the vacuum system.
This destroys the seals and diaphrams in the HVAC , front axle actuator, and any other vacuum operated device that has rubber parts.

I don't know what has been changed in the new switch. I can only assume the design , or seals must be better.
I was told that anytime they have to make a major change in part numbers like this, that there must have been quite a revision, or change in the part that requires such separation from the old part design.

gocntry · Post by **gocntry** » Fri Jun 10, 2005 7:18 am

HenryJ wrote:Ok people, this one is a MUST DO!

Hey HenryJ.... Thanks For The Warning & The Write Up / Pictures

Got Mine At My Local Dealer Today....He's Not As Nice As Your Dealer, Cost Me $35.00

But He Gave Me A New O-Ring For Free

. If This Saves An $1800.00 Repair Bill That Was $35.00 Well Spent. I'll Have It Changed This Weekend.

top_sgt · Post by **top_sgt** » Fri Jun 10, 2005 7:40 am

reed...an o2 sensor socket may work.......i'll try it this weekend and let ya know!!!
i'm going to the dealer for an oil change today.....i'll see if they will change mine for me!!!!!!

Jim · Post by **Jim** » Fri Jun 10, 2005 10:33 am

Got mine today, w/o a body lift I can't even see mine. I guess the hint was when HenryJ wrote "follow the triple vacuum hoses to the switch." Means it's not easy to see

gocntry · Post by **gocntry** » Fri Jun 10, 2005 12:19 pm

Well I Just Did Mine....

Took About 20 Minutes....No Body Lift...Used A o2 Sensor Socket With An 8" Cresent Wrench....No Probs Here....Except For The "Free" O-Ring The Dealer Gave Me Was About 3 Times The Thickness Of The Original One On There So I Just Re-used The Original......

Jim...You Can't See It But Its Right There On The Drivers Side...Once You Follow The Vaccum Hose To Feel Where It Is It's Pretty Smooth Going After That..

Post by **HenryJ** » Fri Jun 10, 2005 2:26 pm

gocntry wrote:... Not As Nice As Your Dealer, Cost Me $35.00

Watch those dealers. List price on my invoice is $34.14. They do have some room to lower the price for you if you haggle with them a little.

My dealer said the GMpartsdirect.com's price was less than their cost. I don't really know why that is, but if you have the time to wait you can always buy it from them.

Glad to hear that it is not too difficult to change with out the body lift.

Anyone else find any ATF residue in the tubes?

F9K9 · Post by **F9K9** » Fri Jun 10, 2005 3:08 pm

I ordered mine from GMPartsDirect last night. I hope it doesn't take to long

gocntry · Post by **gocntry** » Fri Jun 10, 2005 4:39 pm

HenryJ wrote:Anyone else find any ATF residue in the tubes?

None Here Mines A '03 W/ 20,000 On It

Qamar · Post by **Qamar** » Fri Jun 10, 2005 9:20 pm

Hi Guys

Nice information. My question is that my truck model 1996 SD-10, vortec engine, automatic is also having the same switch? I just wanted to be sure before it gets 2 late and major repairs are done due to one small switch

Regards

F9K9 · Post by **F9K9** » Sat Jun 11, 2005 4:21 am

Qamar wrote:Hi Guys

Nice information. My question is that my truck model 1996 SD-10, vortec engine, automatic is also having the same switch? I just wanted to be sure before it gets 2 late and major repairs are done due to one small switch

Regards

I don't know what model years are involved, Qamar.

I do know that I had no problems with my 1997 S-10 ZR2 that had the same engine.

Post by **HenryJ** » Sat Jun 11, 2005 6:18 am

Qamar wrote:... my truck model 1996 SD-10, vortec engine, automatic is also having the same switch?

I don't know what years are affected, or why. The same transfercase and switches are used as far back as 1982. My old 1986 has it , and I have not had problems with it.
This is used on the two speed selectable transfercases. The automatic transfercase does not use the vacuum switch to the best of my knowledge.

Why does it seem to be a problem in the second generation S-series and especially the later models? I don't know. Could it be the differences in the vacuum system? Could it have been a small number of poorly made switches made only for a few years? This may be the most logical explanation. Much like the defects in the engine oil cooler lines.

This switch is above the fluid level in the transfercase, so it should not directly draw fluid when the seal fails. If the case is engaged and the front shaft is turning then the switch would be exposed to fluid , not to mention the switch would be activated and the plunger depressed.
This is a good reason to make sure that the transfercase is not over filled, so as not to have the switch emersed all the time.

My best advise would be to remove and check yours. If it looks good then reinstall and check it again with the transmission service interval.

If you are worried about it, then the $20-$35 spent is good insurance and piece of mind.

AZS10Crew · Post by **AZS10Crew** » Sat Jun 11, 2005 7:38 pm

Now...at the risk of sounding stupid...will replacing that switch cure the HVAC issues or will that require other measures?

Post by **HenryJ** » Sat Jun 11, 2005 7:58 pm

AZS10Crew wrote:...will replacing that switch cure the HVAC issues or will that require other measures?

Other measures.
This is only to prevent the problem from occurring, or to stop it from continuing.
If the system has already been damaged by the ATF , then component replacement is inevitable.

Jim · Post by **Jim** » Sun Jun 12, 2005 3:16 am

gocntry wrote:
Jim...You Can't See It But Its Right There On The Drivers Side...Once You Follow The Vaccum Hose To Feel Where It Is It's Pretty Smooth Going After That..

Did mine with an open-end wrench. I put the truck up on jack stands planning to inspect the location for the purchase of an o2 socket. It's in plain view the wrench goes on straight with plenty of room to work. Since it's not a tapered thread 1/8 turn loosens it. Installation is finger tight, then a slight snug with the wrench...done

gocntry · Post by **gocntry** » Sun Jun 12, 2005 4:04 am

Jim wrote:I put the truck up on jack stands

I Was Too Lazy To Do That

I Just Crawled Under Mine

RocK · Post by **RocK** » Sun Jun 12, 2005 10:55 pm

Thanks HJ

Yer still Da Man.

malkavian · Post by **malkavian** » Sat Jun 18, 2005 2:00 pm

HJ your the man... I have had no issues with mine and I just read this post and I just orderd the new switch for mine also. Ill put it in next weekend.
Thanks again.

F9K9 · Post by **F9K9** » Sun Jun 19, 2005 2:30 pm

Ordered mine on the evening of June 9th and if you are in a hurry do not go the GMPartsFirect route.

Still no valve

Steve2003 · Post by **Steve2003** » Sun Jun 19, 2005 3:18 pm

f9k9 wrote:Ordered mine on the evening of June 9th and if you are in a hurry do not go the GMPartsFirect route.

Still no valve

Same problem here, they just shipped mine thursday.

Steve

F9K9 · Post by **F9K9** » Sun Jun 19, 2005 3:48 pm

Steve2003 wrote:
f9k9 wrote:Ordered mine on the evening of June 9th and if you are in a hurry do not go the GMPartsFirect route.

Still no valve

Same problem here, they just shipped mine thursday.

Steve

Just something to keep in mind the next time.

I just wish I wasn't so stubborn and proud so that I could just go to me "EX" stealership and buy it

Can't sneak around in my Bright yellow crew with the graphics and not be noticed

I even stopped yanking the keys out of the ignition locally after I stopped and thought about it. Who's gonna steal that truck from a noted fananical, armed, retired drug agent

Steve2003 · Post by **Steve2003** » Sun Jun 19, 2005 4:59 pm

f9k9 wrote:Can't sneak around in my Bright yellow crew with the graphics and not be noticed

What graphics are you talking about?

I have a friend who is a undercover DEA in Inglewood Ca. He used to live in Riverside Ca. We used to hang out alot, fourth of july BBQ's pool parties and what not,but then he moved to SimiValley Ca. That's where alot of the LA cops live, the stories he's told me only you would believe Reed! Don't see him much anymore as SimiValley is about two hours away. oh well! I have the upmost respect for you Reed!

F9K9 · Post by **F9K9** » Sun Jun 19, 2005 6:42 pm

Steve2003 wrote:
f9k9 wrote:Can't sneak around in my Bright yellow crew with the graphics and not be noticed
What graphics are you talking about? !

Thanks, Steve but, I may have fumbled what I meant to say:lol:

It's a small town and not too many yellow crews with big black bowties

And who in their right mind would steal a yellow crew with the black bowties in the first place?

A road officer looking for a stolen truck may miss a tag number but, unless he or she is majorly color blind with their face buried in a dozen powdered donuts the crew is safe. Am not saying it could not get gone in the middle of the night and into a chop shop but, SE KY bad guys are too busy cooking meth.

Anyway, way off topic and I hope DHL arrives with my valve tomorrow.

Does anyone know when they added the airvent "cut off" control/wheels to the S-10s? I know my 97 didn't have them but, then I never needed them to turn the vents off when I needed defrost.

Happy Fathers Day to all and to their Dads!

Cajun · Post by **Cajun** » Sun Jun 19, 2005 7:30 pm

Guys,

I just found this forum searching for a solution to my HVAC control switch hiss. I bought a 2003 bright yellow ZR5 with 20k about a month and a half ago and have had the HVAC hiss thing fixed twice. I got my truck back Friday and this time they replaced the HVAC control switch, the 4WD dash switch,the T case switch and in theory they cleaned the vac lines. Saturday after reading this thread, I crawled under for a look. I found green inspection paint on the new T case switch. I guess I'm not done yet.

Question, where do the three vaccum lines go that are connected to the T case switch and how and with what should they be cleaned? How far into the HVAC and 4WD systems can the ATF get? I'd like to make sure that all systems are properly and completely repaired while I still have some warranty time.

The ZR2.com site also notes this issue and suggest that we all call GM to complain. I guess I'll be on hold listening to GM hold music tomorrow.

Thanks for the great site and willingness to help!

coreylubahn · Post by **coreylubahn** » Mon Jun 20, 2005 5:13 am

Welcome to the site!!

Cajun · Post by **Cajun** » Mon Jun 20, 2005 9:07 am

The number to call to complain to GM is 1-866-932-4368. Let me know what you hear from GM.

F9K9 · Post by **F9K9** » Mon Jun 20, 2005 2:49 pm

Just did the swap and I have ATF in two of the three lines

Now what do I do?

I have no symptons other than air coming out my freakin' vents

BTW.........it was extremely easy to swap put and I just used a plain old craftsman 7/8" deep well socket and the old style fine tooth cradtsman rachet that the designer ate Sears up for using his design without compensation.

Now, I have to go out and do it all over again because I was so POed over the ATF fluid in my lines I forgot about the gasket

With the proper mindset and ramps.........10 minutes tops with a BL

I tried the wrench thing like JIM did but mine was to long to work.

Post by **HenryJ** » Mon Jun 20, 2005 4:17 pm

f9k9 wrote:Just did the swap and I have ATF in two of the three lines
Now what do I do?
I have no symptons other than air coming out my freakin' vents...

Well, I'm sorry we didn't catch it sooner.

I really haven't researched the vacuum system so I'm not positive where exactly the lines go. I can tell you that , after finding fluid residue in one of my lines , I checked the lines that go to the vacuum reservoir. It is located in the front fender. Drivers side rear, near the vicinity of the brake booster. I had no fluid there.
I would check the lines at that point, and behind the glove box at the HVAC control manifold.

What to clean it out with?

I would probably try some AC flush, or trans cooler flush. I don't think either would harm the tubing. You will need to get both ends loose so that it does not pressurize , or fill components that are attached.

Reed, if you have a REAL problem, that extended warranty may have just paid for itself

F9K9 · Post by **F9K9** » Mon Jun 20, 2005 4:32 pm

HenryJ wrote:
f9k9 wrote:Just did the swap and I have ATF in two of the three lines
Now what do I do?
I have no symptons other than air coming out my freakin' vents...
Well, I'm sorry we didn't catch it sooner..............................Reed, if you have a REAL problem, that extended warranty may have just paid for itself

Well, thanks HJ

Am Gonna check with my new dealership's service manger and explain it to him. The warranty is now covered by another company.

I know that this is somewhat uncharted territory for us all and I do plan to walk in the shadows but, I am really getting depressed with the corporation that I once worshipped as a youngster.

top_sgt · Post by **top_sgt** » Tue Jun 21, 2005 3:51 am

guess i better get under my 2004 and check mine. i asked the service writer at my dealer about this,,,had a print out from the zr2 website for him. he"didn't" know anything about it!!!hmmmmmmmm
guess some things will be taken care by this "old wrench" and not by the dealer!!

F9K9 · Post by **F9K9** » Tue Jun 21, 2005 8:58 am

top_sgt wrote:guess i better get under my 2004 and check mine. i asked the service writer at my dealer about this,,,had a print out from the zr2 website for him. he"didn't" know anything about it!!!hmmmmmmmm
guess some things will be taken care by this "old wrench" and not by the dealer!!

He is mistaken if, you'd like to be on the optimistic side

He has access to a bullentin

The part number has changed but, it is the same problem.

I pulled my truck up on the ramps in 4 Lo last nite. It took me 5 minutes to get it in 2 Hi this morning.

Document ID# 1350749
2002 Chevrolet S10 Pickup - 4WD

HVAC Mode Switch Inoperative or Stuck in Vent Mode, Oil in HVAC Control Head and/or Vacuum Lines (Replace Transfer Case Vacuum Switch and Contaminated HVAC Components) #03-01-38-009 - (Jun 25, 2003)
HVAC Mode Switch Inoperative or Stuck in Vent Mode, Oil in HVAC Control Head and/or Vacuum Lines (Replace Transfer Case Vacuum Switch and Contaminated HVAC Components)
2001-2003 Chevrolet Blazer, S10
2001-2003 GMC Sonoma
2001 GMC Envoy, Jimmy
2001-2003 GMC Jimmy (Export Canada Only)
with 4WD and Two-Speed Electric Shift Transfer Case (RPO NP1)

Condition
Some customers may comment that the HVAC mode switch may be inoperative or stuck in the vent mode. After some diagnosis, oil in the HVAC control head and/or vacuum lines may be found.

Cause
When the transmission or transfer case heat up, the oil may expand and find its way into the transfer case vacuum switch. This oil expulsion may cause the vacuum switch seal to fail and allow transfer case oil to be drawn into the HVAC vacuum lines.

Correction
Replace the transfer case vacuum switch. Refer to the Transfer Case Vacuum Switch Replacement procedure in the Transfer Case sub-section of the Service Manual. Also, replace all contaminated parts in the HVAC system.

Parts Information
Part Number Description
15664811 Switch -Transfer Case Vacuum
Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
K4120 Switch, Vacuum Control Transfer Case - Replace 0.6 hr
Add Diagnosis Time 0-0.3 hr
Add With Skid Plate 0.2 hr
Any additional time for replacement of HVAC components must be submitted as Other Labor Hours and requires appropriate authorization.

Cajun · Post by **Cajun** » Tue Jun 21, 2005 1:28 pm

I printed this thread out for my dealer service manager. He repaired my truck base on the the TSB #03-01-38-009, same as f9k9 states above which does not indicate the new T case switch part number. The service manager was happy to know that a new part was available, ordered one for me and removed the old number from his data base. FYI, GMPartsDirect.Com still list both parts as good numbers. ???

adrenalnjunky · Post by **adrenalnjunky** » Tue Jun 21, 2005 8:23 pm

I find that TSB interesting that it starts with a 2001 model - is anyone aware of any significant changes for 01 that would make the 2000's not fall under the TSB?

Just curious.

Steve2003 · Post by **Steve2003** » Wed Jun 22, 2005 5:38 pm

I got my part from GM parts yesterday and just did the switch out tonight. I had like a drop of fluid on the little nipple and around the little gasket. I hope I don't have anymore problems but if I do, I have the extended warranty.

Steve

F9K9 · Post by **F9K9** » Mon Jul 11, 2005 1:23 pm

well, I dropped mine off to get repaired this morning at 9 AM and got a call after lunch that it was done

They replaced everything and didn't charge it to my extended warranty but, to GM as a "goodwill" repair since my warranty expired 05/02/05.

The only problem is they replaced my new switch with a new "old part number" one. When I noticed that they had, I retrieved the one I installed back from them. I told them I had a revised switch installed and the whole nine yards but, they pulled it anyway.

Should I reinstall the latest switch?

Post by **HenryJ** » Mon Jul 11, 2005 2:15 pm

f9k9 wrote:Should I reinstall the latest switch?

YES.

Most dealerships have not been notified of the new part yet, and GM has not recalled the old ones yet, as far as I know. I was told it takes months for this all to happen.

The seals in the old switch can and have failed. The new switch is supposed to be better.
I'd install the blue marked switch.

F9K9 · Post by **F9K9** » Mon Jul 11, 2005 2:40 pm

That's what I was thinking

I noticed my blue switch had the O-ring missing and figure it's back with their new green one in my transfer case. The service manager also was the one who said everything was replaced but when I checked the part numbers against gmpartsdirect.com the prices can't add up to everything. The most expensive part was $101 and that was the "control". I had the switch, the control and three actuators on the paperwork.

Steve2003 · Post by **Steve2003** » Mon Jul 11, 2005 6:27 pm

When I got my new switch from GM parts, I didn't know it at the time, but it didn't have the little O ring gasket. So when I switched them out I was sitting at my desk looking at the old one and I noticed the little O ring gasket, and I said to myself, "I don't remember that being on the new part" S**t I am going to have to take the new one off and check it. Damn I didn't want to do that but I had to. Sure enough the new one didn't have it, it's a good thing the one on the old switch was still in good shape. I tell you that's the most work I have done myself on my truck since I changed the fuel filter

Steve

Jeff · Post by **Jeff** » Tue Jul 12, 2005 8:04 am

Well, so far, I have replaced the vacuume switch on the transfer case, did my best to make sure all of the trany fluid id out of the HVAC lines, replace the swelled seal at the selector switch, and things work better, but I still cant get the damper that blows in your face to completly shut. Does anyone know which vacume module controls it, and where it is located. I also had to replace the transfer case control motor because it burned it up trying to switch into 4 X 4 constantly. (500.00) just for the part

df_CrewCab · Post by **df_CrewCab** » Sat Sep 10, 2005 12:51 pm

I just went to do the Hot Feet Fix and noticed fluid in the clear rubber end of the gray vacuum line that I removed. I assume that this is related to this problem. I have already replaced the HVAC controls once when they stopped working.
I just received the new transfer case switch that I ordered and will probably put it on this weekend.
My question is: since I have found fluid that far up in the vacuum lines, is it too late to hope that the switch will eliminate any future problems?

Also, what are all of the components that could be affected by this?

Just trying to determine if the cost of repairs would outweigh the option to trade it in before the problems arise.

Post by **HenryJ** » Sat Sep 10, 2005 1:21 pm

Take loose all that you can and blow the lines out.
Degradation of the rubber parts and diaphrams is a possibility. Anything vacuum operated, ie. HVAC , front axle, cruise control, etc. could be affected.

Stopping the source is the majority of the fix here. You may not have any further problems. How lucky do you feel?

killian96ss · Post by **killian96ss** » Fri Sep 23, 2005 6:37 pm

Thanks Brule for finding this fix.

I replaced mine today with the new one that has the blue inspection paint. My old one had a little ATF in one of the lines , but the other 2 appear to be ok.

I hope the rest of my HVAC system is ok.

The only other thing I did which is not mentioned was to clean the 3 tubes on the connector. I just used some Q-tips with some rubbing alcohol on them. After I cleaned them I applied some O-ring grease also with a Q-tip to the inside of the tubes to make sure they seal up good when connected. This may be overkill, but I just thought I would mention it.

Steve

Post by **HenryJ** » Fri Sep 23, 2005 7:51 pm

Good tip

crew cab sonoma · Post by **crew cab sonoma** » Thu Jul 20, 2006 10:16 am

i just thought this might help. if any of you suspect or fear that oil might have gone up into your vac. lines, you could pull the vac. line off and check it for signs of where it connects.
its between the brake booster and the driver side fender. theres a check valve, and a tee there. thats where the transfer case switch sources its vac. from, and if it is being pulled in, it would have to pass through this line to get to any other components.

i find it unlikely that fluid would find its way into the front axle vac. actuator, as vac. would tend to draw it away from it, and in 2WD, the fluid would have to flow quite some distance uphill to get to it.

in fact, i would think most of the fluid would be drawn down the vac. line to the intake manifold.

Post by **HenryJ** » Thu Jul 20, 2006 11:52 am

I have heard stories of the vacuum reservoir being filled, as well as so much in the system that it was leaking into the ashtray from the HVAC controls.
Thanks for the tip on the vacuum source

BADs Crew · Post by **BADs Crew** » Thu Jul 20, 2006 1:59 pm

Just this week I noticed that the two AC vents on the passenger side of my dash are blowing very little air. The two on the drivers side will blow your hair back. Do you think this could be the problem?

mattfu · Post by **mattfu** » Sat Sep 30, 2006 6:05 am

i am having same problem, all air comes out of vents, i have to manually shut the vents off to get any defrost or floor air. no problems with 4x4 or cruise or anything else. i am picking up a new t-case switch in 2 days ($75 in canada) , my question is for those of you who have done this repair allready, have any of you had contamination and simply replaced the switch? did things go back to normal? i assume my contamination is not to the extreme since i only have one symptom and other guys have 4x4 problems, etc. , Any of you guys that had the air vent problem only simply replace the switch or did you have to flush lines and replace the controls just to get things back to working order??? i know i will have to flush and clean anything i find wrong but im just wondering if i can replace the switch for now to get things working then tackle the rest at a later date.

Post by **HenryJ** » Sat Sep 30, 2006 6:11 am

mattfu wrote:... im just wondering if i can replace the switch for now to get things working then tackle the rest at a later date.

Replacing the switch will eliminate the source of contamination and correct issues with the front axle engagement. It will not repair the damage that has been done to the HVAC system.

F9K9 · Post by **F9K9** » Sat Sep 30, 2006 6:12 am

I had everything replaced and the air still comes out the vents. I think it is the nature of the later models. My '97 never had a hot foot problem or methods to shut off the vents.

Post by **HenryJ** » Thu Oct 19, 2006 3:32 am

XxsilentjayxX wrote:well i pulled my truck into work today to take a look at it... bad news.. i have the old valve on it and there is a LOT of fluid in my lines... i have to find time to go get the new one and get my new tailgate cables(free, YAY!!) from the dealership

'03 S-10 4x4, V6

2kwik4u · Post by **2kwik4u** » Fri Dec 22, 2006 7:40 am

Anyone know if this is a pressing issue on the '04 models?

I'd like to think by the age of this thread that GM would've switched to the new valve shortly after finding it on models still being produced on the assembly line.

Is there an inspection other than the colored ispection mark? I'll have the truck on a lift next weekend, and would like to inspect/fix this issue while there.

F9K9 · Post by **F9K9** » Fri Dec 22, 2006 2:15 pm

2kwik4u wrote:..........I'd like to think by the age of this thread that GM would've switched to the new valve shortly after finding it on models still being produced on the assembly line.

Is there an inspection other than the colored inspection mark? ...........

This thread started last year. I'd inspect it and change it if it is the incorrect one. Most of the dealers never saw the TSB and they didn't use the updated part when they did. My dealer used the older part after I installed the modified one. I went back and got the improved part (that I purchased from GMPartsDirect.com) from the dealer and reinstalled it. To the best of my knowledge, the color is the only way to tell. Replace it now or pay hundreds later.

Wrangler · Post by **Wrangler** » Thu Feb 15, 2007 2:14 pm

any part numbers on the hvac controls that need replaced mine only blow from the front vents. Hard to defrost a windshield from those vents. LOL This truck is gonena nickel and dime me to death compared to my 1995 Sonoma.

F9K9 · Post by **F9K9** » Thu Feb 15, 2007 4:41 pm

I just close the vents in cold weather. My '97 never had an issue like these do. The '97 never had a way to close the vents so, this may be normal for the later models

2kwik4u · Post by **2kwik4u** » Fri Feb 16, 2007 7:20 am

Took some pics of my switch while the truck was on the lift the other day (ok about 2 weeks ago). Can someone verify this is the right or wrong switch?!?!? Did I even take pics of the right thing?

Last two pics of this album

The 4wd still works great, and the heater vents still work, so I's think the switch is still good. I'll have the truck back on a lift in a few weeks, so I can change it then if needed.

Thoughts?

LonestarZ · Post by **LonestarZ** » Fri Feb 16, 2007 9:03 am

Can't really tell in those pics.. If the switch has a green stripe, (and it should be a green stripe since GM did not "fix" the issue til the '05 models) you need to replace it.
It is not a matter of if the part will fail, but when the part will fail. Better to replace the part before it fails.

I have on mine.

Post by **HenryJ** » Fri Feb 16, 2007 11:03 am

For $20 , I would buy a new switch and change it. If you find it has the correct inspection mark keep it for a spare or a friend in need.

2kwik4u · Post by **2kwik4u** » Fri Feb 16, 2007 11:57 am

HenryJ wrote:For $20 , I would buy a new switch and change it. If you find it has the correct inspection mark keep it for a spare or a friend in need.

I saw that, and asked the local GM dealership while I was in there the other day for some unrelated parts. He quoted me like $45 for that switch.

If I can grab one for $20, I'll definately replace it.

LonestarZ · Post by **LonestarZ** » Fri Feb 16, 2007 1:18 pm

gmpartsdirect.com

Wrangler · Post by **Wrangler** » Sun Feb 25, 2007 11:35 am

My vent selecter switch is now hissing. Anyone have a part number on this so I can order the new transfercase switch and this at the same time. I am working 56 hours a week so the dealer is closed by the time I get off work to ask them. Thanks

S-10CREWCAB.NET

Revised transfercase switch *READ THIS THREAD!

Revised transfercase switch *READ THIS THREAD!

Must read!