A/C not working when car is stopped (compressor only turns on for a few seconds at a time)

I have a 2008 Chevy Equinox, and have had issues with the air conditioner for a while (see my other post: http://community.cartalk.com/discussion/comment/2957278#Comment_2957278).

Lately, if the car is stopped in traffic or at a red light, I cannot get any cold air. The compressor will turn on, but only 2-3 seconds, then it shuts back off. It will cycle like this, on and off, about every 10-15 seconds while I am stopped. Each time this happens, the RPMs jump and the car lurches forward a little as well. As soon as I start moving at a decent speed (20 mph or so), the air gets cold again.

The recommendation from my other thread was to replace the heater control module - do you think replacing that part would fix this too, or is something else going on here?

Thanks for any suggestions!

Did you get the software update from the TSB?

I did (last summer), but it didn’t seem to help anything. I found a heater control module online yesterday for $35, which is why I made this post…I went ahead and bought it, figured I’d roll the dice. If you know of any other possible causes, though, I’m all ears.

The symptoms you describe could also be the result of the radiator fan not engaging properly.

I had virtually identical issues last summer – When idling with the AC on, the compressor would kick off, and the car would buck as it felt like it was going to stall (RPMs drop and then surge).


It sounds like the compressor may be short cycling . . . usually due to a low refrigerant charge

Another possibility is a defective clutch cycling switch . . . should be located on the accumulator

Just throwing some ideas out there . . .

Sounds like it needs to be recharged and the clutch is kicking out they will do that if there low on Free on and oil

My vote is for the compressor short cycling due to the refrigerant being a bit low.

Do the electric radiator fans run anytime the A/C is on? They should…After you check that, check the high and low side pressure with a proper gauge set…

well the new control module didn’t solve any of my problems, oh well. thanks for the other suggestions, I’ll start working through them asap