So Saturday I noticed I can no longer change the direction of my HVAC air. It is stuck on the dash vents. I can't get it to change to floor/defrost/etc. It still turns on and off. Also you can still adjust fan level and heater temperature. I just can't change the direction.
Now, I did do some homework around the site before posting this. However, I think I may be confused on some things. I read something about a switch leaking ATF into the vacuum lines?? Do they really have the HVAC and the transfer case tied in?
Somebody please clarify and helf a GMC newbie. Thanks everybody!!!
jhowell0o wrote:while examining the vacuum hoses I broke a t-valve. So I went to the auto parts store bought a new one and while examining the broken t-valve I noticed it was clogged. Bought a new one, put it in, and now I have heat on the floor, defrost and front. All works now!!!!! It is amazing how you break a part when examining it, and it was the defective one all along.
Check for bad hoses and loose connections. the short piece behind the brake booster tends to dry rot.
HenryJ wrote:
Pull that grey hose off of the vacuum pot (upper center) to see if there is vacuum in the system, it should always have vacuum. Now if that does have vacuum , take loose the red line. Mine has a tee installed in it for heater control. This line should only have vacuum when in the defrost positions.
If it has vacuum all the time there is a problem with your control mechanism.
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.
Now if you have no vacuum that is another problem, and maybe harder to find. start by following the vacuum lines that head for the rear drivers side inner fender. This is where your vacuum reservoir is located. Make sure there are no leaks. Then check the lines to the transfercase and front axle actuator, if it is possible that they may have been disturbed when offroading.
"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving! - ThunderIIKE7CSK
Are you able to do some trouble shooting yourself?
I would check the transfercase switch and work up from there. Who knows? You might just have a bad control head.
"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving! - ThunderIIKE7CSK
Ya, between my dad and I we are pretty good at troubleshooting and checking things out. These trucks are so new/foreign to me that it will make for a new adventure. lol
Is this type of problem fixable without replacing half the dash?
Maybe. Do some checking and see just how far things will need to go.
What year truck?
"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving! - ThunderIIKE7CSK
I also have an 03 CC and had the A/C control switch replaced twice and the transfer case vac. switch replaced twice and the 2WD/4WD dash switch replace as a result of ATF in the vac. lines before the dealer got it right. I had to bring the dealer the service bulletin with the replacement part number on it because the new part number was not in their data base at the time. The tale tale sign of ATF in the line is to look in the ash tray to see if you have any visible fluid there. Fluid eventually drips there from the A/C switch located just above the ash tray. If you see an ATF film there, than there is no real need to crawl under your truck.
If you only have 34k on your ride than this, now well documented GM short coming, will be fixed under warranty. If you are just over your warranty, I'd still bring the service bulletin to your dealer and request a good well repair. You have nothing to loose.
Well it was exactly what everybody said it was. Unfortunately I never had the time to get at is myself and it ended up at the dealer. $800 bucks later here I am writing this message.
It's not so much spending that amount of money on my truck that kills me. Its the fact that it was put towards something that should have worked all along.
SonomaCrewCab wrote:Well it was exactly what everybody said it was. ...
And that was?
"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving! - ThunderIIKE7CSK
If you only have 34k on your ride than this, now well documented GM short coming, will be fixed under warranty. If you are just over your warranty, I'd still bring the service bulletin to your dealer and request a good well repair. You have nothing to loose.
"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving! - ThunderIIKE7CSK
Do they really have the HVAC and the transfer case tied in?
