Over heats while idleing unless air conditioner is running

When you place your controls on defrost it turns your air conditioner on - depending what the heat level is set on the air conditioner will cycle on and off to regulate temp. Anytime the A/C runs the idle sensor will bring the idle up

The air conditioner runs off of the motor and takes a good deal of power away from it. I ALWAYS shut my air off when preparing to pass a vehicle or getting on an on ramp.Unless you have a diesel or a V 8 the air conditioner will affect your performance of the motor greatly.

IDLE SPEED COULD BE TOO LOW.IDLE SPEED SHOULD BE 800 RPM. IF IDLE SPEED TOO LOW AND ENGINE NOT WELL TUNE UP AIR CONDITIONER WILL PUT LOAD ON ENGINE CAUSE ENGINE OVER HEAT AND SHUT OFF.

try to see the connection if still good..replace it if not...and see the fuse if still working

that weired they normaly die when the air con turnes on ummmmmmmmmmmmmm check the air filter

turning on a/c should automatically increase the idling, so that's where your problem is. need to look at the system where the throttle is open a bit when a/c is turn on

Is the fan running with A/C on at idle? If yes try blowing out the radiator and condenser with compressed air.

it sound like one of the flap in the duck work is not working. check your heat contrell unit in the dash

The "Tachometer" is the gauge that indicates the engine RPM. It is not unusual for the idling RPM to drop slightly when the air conditioner comes on. The air conditioner represents a fairly large load on the engine so when it starts, the RPM will drop slightly. When driving, you'll probably not even notice that the air conditioning is a load on the engine unless you're accelerating uphill, pulling a trailer or passing another vehicle while the vehicle is fully loaded. At idle, the Envoy's computer should detect the falling RPM and make adjustments in fuel delivery to bring the RPM back up.

In any case, it shouldn't be cause for alarm, unless the air conditioner is stalling the engine. If this is the case, you are probably in need of service. The issue of low cooling from the air conditioner while idling in gear (as is the case when stopped in traffic, etc.) is correctable free of charge at the dealership on certain vehicles as a result of a recall. Your dealer can tell you if your vehicle is affected or if there is other recall work pending on your vehicle based on the VIN.

I hope this helps!

It sound like thermostat problem, maybe it work too hard when you turning the cold air.