My car keeps cutting off. I got the starter, alternator and battery checked. They all were fine. I noticed it happens when the A/C is on. What could it be?
My car has an automatic transmission.
The A/C system depends on the drive or serpentine belts driven by the motor to work. If the A/C is putting extra load on the engine, the engine will suffer and can stall. You will want to start by watching the belt as the A/C turns on. This needs to be done carefully: if the belt breaks or comes off, it can hurt anyone standing too close.
If you do not see any obvious damage or issues, it’s time to dig a little further. With the car off, look at the A/C compressor and the pulley. If the A/C compressor is pulling too much power from the engine, it will likely need to be replaced. The pulley should also be inspected to make sure it is spinning freely as it should.