Greetings all; I am a new TC owner (85' light blu/grey vinyl, with 40K miles).

When sitting at idle I could hear something loading the engine 3 seconds on/ 10 seconds off over and over again. I popped the hood and saw a plate on the end of what I think is the AC compressor spinning and stopping.

The AC seems to work ok when I turn it on (though winter isn't exactly the best test time) however the question is, why should that be running at all when I have the AC off and its 40 degrees outside?

Greetings all; I am a new TC owner (85' light blu/grey vinyl, with 40K miles).

When sitting at idle I could hear something loading the engine 3 seconds on/ 10 seconds off over and over again. I popped the hood and saw a plate on the end of what I think is the AC compressor spinning and stopping.

The AC seems to work ok when I turn it on (though winter isn't exactly the best test time) however the question is, why should that be running at all when I have the AC off and its 40 degrees outside?

I didn't know this happened on the older ones but I know the newer cars cycled the compressor so that they don't seize (or freeze up), don't know what the correct terminology is but basically it does it so that it'll last longer.

Perhaps that is the answer, but when I took it in for a buyer's inspection the service guy said that sounded like "short cycling" To look into that would be more money than just the $90 buyer's inspection, and AC can cost up to $2000 for difficult bugs.
I didn't find him very helpful, though perhaps his boss likes him.

If you have the ATC on, the compressor runs regardless of outside temp. It also runs in defrost. This is to dehumidfy the air into the cabin and prevent a windshield fog up.

wouldn't it cycle a lot if it were low on refrigerant?

wouldn't it cycle a lot if it were low on refrigerant?

yes it would, or if your a/c clutch is going bad like mine is lol... mine cycles on and off and clicks REALLY loud when its on lol... luckily my system drowns it out cause im too lazy to fix it...

I have a 98 TC and this has happened twice. It possibly is the low pressure sensor that screws on the side of the dryer. I paid $13-15. for the thing and it takes all of 5min to install. Just disconnect the socket from it and unscrew the old one and reinstall the new with the reverse proceedure. I got mine from a local shop that does heater and air repair for cars. Also check the radiator fan and make sure it is working, because if the system isn't receiving the amount of proper air flow it will automaticly turn the ac off and on trying to keep the engine from overheating.