Wierd A/c Gremlins-help!!!!!!!

[YESZREE]

Wierd A/C Gremlins-help!!!!!!!

There are things going bump in the night.

Without touching any buttons, the A/C temp setpoint re-adjusts itself to 75 deg. Thats not all. Sometimes the "auto" button activates all by itself!

Another anomoly is if I press the "auto button" and adjust the temp setpoint @ 60 (coldest) the A/C works fine. If I adjust the temp to say 73 deg.F. the system runs for about 10 min. and then slowly the fan speed begins to decrease untill it almost stops.

What is going on? HELP!!!!!!!!!!!!

:confused

 

[JT ZR-Won]

"They're here......"

I wonder if you have a possible short in one of the wires behind that panel??

Jay

 

[Chick]

I think it's the heater control unit in the dash causing the problem by the symptoms you describe. Part number #16152503 list price around $250.

 

[Chick]

Labor time if you have it done is around 2 hours.

 

[jmccloud]

From left field

My Dad has a 92 Park Ave with electronic A/C that behaved very similarly. I tried to find the outside air temp sensor since that read incorrectly too. Looked all over the cowl inlet, etc. Finally took it to the dealer when the hot weather arrived. I think the part was <$50 but they socked me for 2 hours labor.
When I raised the hood the embarassment hit. There it was right in front of the A/C condenser (behind the grill). I could have done the job in 5 minutes. The electronic A/C worked fine after that.
Good luck finding it.

 

[marteeni]

I just replaced my temp control unit in my wife's '94 convertible. Cost just over $100 from http://www.gmpartsdirect.com and took an hour. Her's was doing some strange things as well and the new unit fixed the problem.

Good luck!

 

[YESZREE]

Thanks for all the suggestions. I've replaced the ambient sensor. Problem is still there. I needed to replace the sensor anyway as it was missing when I purchased the car!!!!

I've been out of town for awhile so I haven't been bugged by it lately. I have a shop relpir manual. I'll chech the troubleshooting tree.