A/C Compressor running constantly on my '99 hoe

[willie1280]

when i had my OBS denali the compressor clutch would scream so loud i wouldnt be able to hear the radio. i just pulled the plug right from on top of the compressor

Yup, squealing = fried compressor

 

[03z71chevy]

Having the same problem with the compressor always on and read through this earlier. My compressor is always on whenever the panel is on. If I just select the panel or bi-level (vent) the compressor runs and blows cold air. I do have the snowflake off, defrost off, auto off, recirculate off and rear a/c off.

I did discover today that the compressor does turn off if I turn the whole panel off. I think this means that the PCM is not the problem but I don't know what it could be. The whole panel? Please help!

 

[SunlitComet]

unplug the control head panel if it is still on on your swap the a/c and starter relay and starter is still normal and compressor is still stuck on you either have a bad output driver on pcm or a damaged wire somewhere.

 

[03z71chevy]

Thanks, I should be able to get to all that tomorrow. I figure if I unplug the panel the compressor will stop since when I turn the whole panel off the compressor also turns off. I thought the problem the original poster had was his compressor was running whenever the engine was. Was hoping that meant my PCM was not the issue but I don't know.

 

[SunlitComet]

Wait so when fan switch is in off position the compressor shut off but all other times it stays on? If Travis the case the control head is at fault assuming you a/c button is out AND you do not the node switch on any setting that blows on the windshield. Those deafrost settings are a automatic compressor engagement.

 

[03z71chevy]

That is correct. If all temp. control settings is off the compressor will shut off. If just the fan is on in any setting the compressor is on. It will not allow me to run just the vent without the compressor.

Is it worth looking into getting the control head rebuilt or should I just look into getting a replacement? Hate to buy a used one with the same or new problem.

 

[SunlitComet]

amazon sells new delco units for about $130. this unit replaces 1996-2000 OBS SUV's.
http://www.amazon.com/gp/product/compatibility-chart/B000C9GYOA

 

[03z71chevy]

Yeah, mine is an 03 so that won't work. I know I am in the wrong forum but I figured this problem was going to be the same in pretty much any generation Tahoe.

That gives me a place to start though. Thanks for the help.

 

[SunlitComet]

your system is based on sending data to other modules to tell them what to do as opposed to just sending a volt circuit here or a ground circuit there. but the end effect is the same. if your control head shuts it off when turned to off and on any other time is has to be a mode you are set on or a short in one of the switches. review your manual on hvac use to be sure it is not something you are doing before replacing or fixing yours.

 

[03z71chevy]

Thanks. I did read my manual but I am also somewhat familiar with the system. When everything but vent is off it still runs the compressor and that can't be normal.

I thought the climate control module was the problem as well but I never had a vehicle that had this problem before. I did find new one's identical to mind for just over $100 on amazon so that's still not bad.