I have a 2004 gmc envoy and when I turn on the AC at low speeds the engine cuts out. The check engine light is not on. Its a in line 6 cylinder. The car seems to be running great until I turn on the AC
Does the air conditioner get cold when it does work?
If it doesn't get cold then there is a chance the A/C compressor may be locked up. I don't think this is the cause but you need to see if the air conditioner compressor clutch moves when it is engaged. If it seems to work properly, engages properly and gets cold then we can move on.
A common cause of an engine to turn off or stall is the throttle plate accumulates a thick coating of carbon, it's called coking. The throttle plate needs to be cleaned with a throttle plate cleaner or carburetor cleaner and a rag. Clean the plate area and also remove the idle air control motor (IAC) and clean it also. It could be caked up with carbon and not be able to move properly. The IAC motor raises the idle when the air conditioner is turned on so it can compensate for the engine rpm loss from the load of the compressor being applied.
If it still stalls, then see if you can get someone to check the engine out with a scanner to see the engine data when the engine stalls. A trained technician can see any abnormal data and identify any problem that may be causing the engine stall.
Check out the charging system to see if the charging rate is up to specs. Low battery voltage/amps can cause a stall by not having enough voltage in the battery to supply the extra voltage needed.
Try these suggestions and get back to us when you can with the results. We can go on from there.