Vinnie T

The last 2 times I’ve started the car after it sitting about a week, the A/C compressor kicks on along with the radiator cooling fan on low even if the A/C controls are switched off. I can shut down the entire HVAC system and the compressor and cooling fan continue to run. I don’t use the AUTO setting at all, but it also had no effect on the compressor cycling either when I did test it. The first time it happened, I thought I might have left the A/C switched on before shutting the motor off, and maybe the relay stuck in the on position. I usually shut the A/C down well before parking the car since I like to get the excess cooling air out of the vents.

I found the compressor relay in the fuse box and pulled it out. Checked the contacts which were clean, put it back in and started the motor. No compressor running or cooling fan this time, and the compressor was cycling on and off like normal. It also was controllable with the manual on/off switch. Thought that was the end of it until it did it again today. Pulled the relay and re-inserted it, and all started working fine again. I know for a fact the A/C was switched well before shutting the motor down last week, so the relay shouldn’t have been in an “on” sequence at that time. It seems to work fine on restarts the same day or within a day or two.

It’s almost like it’s getting an odd command from the computer to start up shortly after the motor starts after sitting a while. Unsure if I should just get another relay and keep my fingers crossed it isn’t something else or just take it in when I get a chance (still under extended warranty) with no guarantee it will be stuck in “on” when it gets to the dealer. Anybody else have this happen or have any other ideas?

ChevyDave

at first i thought of switching #35 (i assume thats the one you were pulling) with another to see if that stops the problem. but after rereading your comments, i can see how you thought... if you didnt have it on when you shut car down, the relay couldnt be left in 'on' position. i'd still switch it with another, for final test.


someone here in the last week (maybe you) said that when they started car the fans came on, even when the car was cold. i never heard back what they found. they were gonna check the fan connector and relay

Vinnie T

Yah, #35 is the relay in question. Maybe I'll swing by the dealer on Monday and see if they have one in stock before taking the car in. I really thought getting it to reset last week did the trick after it was functioning properly after that. Maybe I'll also try disconnecting the battery to see it that might also get the HVAC electronics to reset also.

ChevyDave

no need to purchase another relay, just switch it with another like one there. thats how most test them.

Vinnie T

I'll be damned! I didn't even notice that the smaller relays were all numbered the same. I'll give it a try tomorrow and then re-test it next week since that has been the pattern. Thanks for the heads up!