Jeep 2002 GC heater/fan problem

[HawkeyeScott]

Posting for my mom who asks for some help in diagnosing this newly-found problem on a 2002 Jeep Grand Cherokee Ltd. they bought last year and have basically parked since then. Here is what she emailed today:

"Need help with the heater on the white Jeep. Worked ok this morning but on the way home the temp. lights(temp for both driver and passenger) went out and I noticed that it got cold and fan wouldn't work. When I got home I messed with it and found that the lights and fan would come on for about 2 seconds and then shut off. Didn't know if you could post it and find out what might be the cause-a short, fuse or I just don't know how to set it. However, I did nothing different from this am."

Could it be related to sitting for a long time without many starts? Thanks guys.

-Scott

 

[OVERKILL]

IIRC, these things are known for serious issues with their climate control. A buddy of mine had one. It would only blow cold air, and apparently they are a nightmare to fix.

 

[VNTS]

Go to jeeps unlimited, search blend doors.

They are operater by motor to modulate and they have plastic shafts wiht stops which strip and blend door falls open on one side allowing cold air to pour in.

http://www.wjjeeps.com/climate.htm

 

[meep]

This sounds less like a blend door (The #1 hvac issue with these cars) and more like a controller or wiring fault. The fan may be powered by a circuit breaker and not a fuse-- if the motor is worn and pulling too much load, it could be popping the breaker. = new fan. BUT if it's fused, then my bet is the controller. Don't know if there's a separate module for hvac or if it's the body computer. This one could be tricky to trace.

M

 

[VNTS]

THe link above has all the info you need to troubleshoot.

It is probably a broken stop on the blend door. He will have to rip the dash apart. There are better aftermarket parts to replace the shafts on the blend doors. it is discussed Jeeps unlimited board.

I have an 02 WJ Laredo, has the manual AC and I am glad I dont have the stupid climate control. Simple is better

 

[J_Sap]

If it has sat for a year did an animal build a nest in the air ducts or the blower fan? It would make sense why it runs for 2 seconds and then cuts out. I had that happen to me on one of my cars, it was a mess getting all the junk out of there. About a month or two later my blower fan rusted up and died so I had to replace it.

 

[HawkeyeScott]

Thnaks guys. I appreciate the variety of responses.

I had a question about the servo motor theory - what about the lights going on and off? I haven't read anyone with a servo motor/blender issue say anything about lights. I had a servo go out in a Crown Vic once and all the lights stayed on as they should.

Thanks again.