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

Maintenance/Repairs
1

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!

2

Did you get the software update from the TSB?

3

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.

4

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).

5

@crj123082

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 . . .

6

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

7

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

8

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…

9

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