I've noticed that when I turn on my heater and I'm at an idle my a/c compressor comes on and goes off every few seconds.It makes my idle fluctuate a couple hundered rpm when it does it and it's annoying.Anybody have this happen?

 

same here... and when the a/c is on it doesnt blow cold but I can feel the lines are cold

 

Mine blows cold when I have the controls on cold but if I want the heater on then the compressor just comes on and goes off in about 5 sec cycles.

 

also someone mounted the switch to the electric fan to the a/c so when i have it on the a/c goes on wasting my gas.. I'm thinking they messed up the wiring??

 

Just to clarify... this is when your controls are set to vent, defrost or heater? Because if you have the A/C selected (Max, Norm, Bi-Lev) and you flip the temp to hot, the compressor will still come on.

Can you explain that please? Are you saying that someone wired in a switch so that when you turn on your blower motor, it turns on the A/C?

 

Yep,I can have the controls on defrost/hot and it blows hot but the compressor still kicks on.If I have the a/c on it stays on.

 

all cars do that

 

All cars a/c compressors run when the heater is on?None of my other cars do.

 

I agree, mine don't either. You might want to check your HVAC controls, as some wires might have been worn down and things might be crossing over. That's all I can think of at the moment...

 

like Jproz1167 said ALLcars do it. If you have your defrost on your a/c compressor will kick on and than turn back off. Every single vehicle out there does it if you notice or not, even all the new cars. Most people dont realize it or able to tell depending on the cars it is easier to hear the a/c compressor kick on.

 

Yes, it comes on with defrost selected. But with the vent and heater, it does not.

 

than it is working as designed

 

It does it on every setting.

 

fbird92... 87tpi has the problem, not me. His A/C comes on with the vent and heater settings. I would suggest finding another HVAC control unit from the junkyard and see if that solves your problem. I'm looking at the wiring diagram and nothing looks like it would cause that to happen, so maybe your control panel went south.

 

I agree with Super_kev you may have a bad HVAC head unit.But as others have stated the compressor does come on when you select defrost.This is done to control humidty.The compressor short cycling,cutting in and out very often,could be a sign the system is low on refrigerant.

 

What I mean is the car has a manually controlled electric fan wired to the A/C, so when it starts running hot you have to put the A/C on, which is pretty much a waste of gas/power

 

Your fan temperature switch is probably wasted and needs to be replaced.