2002 fan relay

[lakefolk]

man im so glad i found this forum...

I have a 2002 crew cab v-6. the heater blower only blows on 3 & 4 speed.. nothing on 1 & 2.
At least i have heat LOL!! Id like to fix it though and by reading some of the prior posts i have eliminated any fuse problems, they are all good.. so now im thinking either relay or resistor.. can anyone tell me where these are located??
i think i know where the resistor is but want to be sure. i have found what i believe is the resistor on the passenger side in the duct work on the firewall approximately just below where the passenger windshield wiper connects.. is this correct?? is there a way to test it???

how about the relay??? anyone know where it is located??? is there a way to test it??

thanks in advance for any help anyone can provide..

[HenryJ]

Welcome aboard
You are on the right track for the resistor. It is in the top right hand portion of the HVAC housing in the engine compartment. You can test it with an Ohm meter. Even a continuity test will tell you if it is working.
The blower motor relay hangs from the firewall just above it. The high speed setting should be controlled by the relay.
Unfortunately I believe the control switch has been a problem in the past. It may be your next suspect.

[lakefolk]

excellent!! thanks a lot for the reply..
so would you suspect the resistor 1st?

concerning the switch; is it a hard fix?

[HenryJ]

I think you will find the resistor tests out ok. It can be tested by removing the connector. Pretty easy to do. The resistor controls the lower speeds and since it is your high speed only having problems, I would say the resistor is working as it should. The resistor serves to lower the voltage , which slows the fan speed. More resistance , slower speed.
The high speed setting does not go through one of the resistors. It goes through the relay so the blower receives the full 12 volts. This is the high speed.
I think you are wise to check that relay. Hold onto it and see if it clicks when turned on. If it does then you know that at least the switch is activating it. If it does not, then check to see if it is receiving the signal from the switch, or if it is failing to operate.
Pretty straight forward trouble shooting. Let us know what you find.

Replacing the switch is not too bad. Tearing the dash all apart in not all that much fun. Time consuming is the best description that I can muster.

[lakefolk]

actually it is the high speeds that are working (setting 3 & 4) it is the low speeds that are not (settings 1 & 2)

[HenryJ]

My mistake I read it backward.
Yes , suspect the resistor and test it, but still think about the switch. Is is a much more common replacement item.

[lakefolk]

will do...

Thanks very much!!!!!!!!!!!!!!!

appreciate your help!!!!!!!!!

do you know the test procedure by chance? i have a decent meter..

[HenryJ]

You should have four terminals on the resistor.
A - LT BLU - med 2 from switch
B - BRN - low from switch
C - DK BLU - to blower motor relay 87A (NC)
D - TAN - med 1 from switch

Test for continuity C-A , C-B, C-D

The values are not listed for resistance. Testing a known good replacement part would be as good as I could do should I need to know.

NAPA lists a new resistor for under $17 The switch is listed as just over that. Neither in stock here.

[lakefolk]

cool!!!

thanks again!!!!!

[lakefolk]

have a .9 reading between between C-A, no reading on the other 2.. looks like resistor time!!!

thanks again for all your help!!!!

[HenryJ]

Test the new one before installation to confirm your tests results. Look for damage or an accumulation of debris as a reason why it may have failed.
Add a little sealer to the outer edges on installation.
Let us know how the story ends

[lakefolk]

i'll definitely do that and post my results back here.. Hopefully someone in the future can benefit from this thread..

great site!!!!

[rlrnr53]

I had to change the resistor on my crew about 3 weeks ago. Temps inthe single digits of the morning,convinced me that the 15 or so dollars would be wellspent. I had to wait until things calmed down at work before I had tim to change it. even though it is a 15 min job, 12 to 14 up to 16-18 hr a day doesn't give you much time to do anything other than work eat and sleep.

[tvc15]

I had the same issue with my 2001 CC just 3 and 4 fan settings. Replaced the resistor module and it works fine now. One of the diodes(?) looked a little crispy when I took out the old unit.