'07 Escalade - AC issues

Question

2007 Escalade AWD.

Yesterday, I noticed that the air conditioning keeps turning on and off.

To clarify: the control unit does not indicate that it's turning off. I still have the fancy snowflake icon, temp set to desired level, etc.

Air will blow cold for a few seconds, then warmer, then cold, and so on. After the car has been running for awhile it seems that the period of on/off increases, but it never gets back to 100% on.

We're in Dallas, and I can tell you that global warming is real. Temps are well over 100° (F) lately.

This happens if the car is stopped (idling at a light), moving, or whatever. There appears to be no correlation between vehicle speed and AC functionality.

The car is not overheating.

Oil was changed by a local shop about a week ago, otherwise no recent service.

I'm going to put some UV dye in the system and look for leaks, but I'd be surprised if one randomly appeared. It feels more like the compressor is periodically engaging / disengaging, and I'm not sure what would cause that to start out of the blue.

Thoughts?

Answer 1

First you should get a service for your AC. All AC´s more or less slowly leak coolant gas. If it has last been serviced 2 or 3 years ago, chances are you are simply running low on coolant. If there is too little gas in the system, it either shuts off - or it can even get damaged.

If, after a refill of your AC, the Problems prevail, check the AC compressor clutch relay (as @Al_ mentioned) and the clutch itself, in that order.

Answer 2

Since this was asked three years ago, my guess is either a problem occurred in the hvac controls or a leak occurred from normal war and tear. Industry guidelines use several grams of refrigerant leakage per year as the maximum for a sealed system. 28.3 grams per ounce. GM uses either a combination low/high pressure sensor (two wire type) or transducer (three wire type) to sense lower than ideal standby pressure on the discharge side or excessively high pressures, signaling the ecm to disable power to the compressor clutch coil. Standby pressures are around 70-90 psi in summer temps. High side operating pressures are between 125-250+ psi. When a leak occurs, refrigerant, oil and dye are released with dye and oil marking the leak site.

UPDATED 6/7/25 In addition, did anyone check for faulty/dead cooling fans? A large suv most likely uses two cooling fans, and possibly three speeds. Fan speed would change on coolant loads, ac demands, outside temps and humidity. Texas heat would probably force cooling fans into high speed to cool off both hot radiator and condenser coil. At least one GM car I owned had dual fans for low, medium and high speed. Resistors were used to control low or medium speed and one fan resistor burned out. replacing it fixed it for awhile but it failed, requiring fan replacement (after 10+ years of NYC summers). If one fan is faulty, ac pressures may rise from the condenser coil not cooling off, well above safe operating pressures. Detected by the ac pressure sensor sending signals to the ecm. The ecm is programmed to disable power to the compressor from excessive high pressures until pressures drop below maximum (approximately 400+psi). This may explain the compressor cycling on and off; lack of adequate fan cooling off condenser coil and radiator. This presumes a full charge of refrigerant.

For my previous GM '03 car, low speed fan cooling is immediate when ac is turned on. Very quiet and is seen with hood open or looking thru the grille. Medium speed as radiator and condenser coil temperatures rise. High speed while stopped (parking, lights, idling for longer than a few minutes). High speed fans were heard, cycling from medium to high speed while parked in hot and humid weather. Electronics governs cooling fan speeds according to coolant and ac pressures (pressure sensor in the ac system).

Answer 3

One thing you can check is your cabin filter. A dirty cabin filter can cause insufficient air flow around the evaporator core on the inside of your vehicle causing a block of ice. Unlike heat pumps and truck reefer units car A/C units don't have a defrost function and tend to ice if left on MAX A/C with recirculation function on too long.

After you change your cabin turn the highest temp A/C on (at night when it ain't 100 degrees) to melt the ice. When you stop you should see about a 6 ft diameter puddle of water under your vehicle. Then it should chilling like usual.

To prevent this don't drive at max cold after interior gets comfortable then just slightly increase the temp a bit to keep the condensate liquid enough to empty out.

Answer 4

It could be your climate control switch it's in your venting underneath the dash on the passenger side my friend had a similar issue and it turned out to be that. Good luck:-)