Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
is the ac compressor turning when the clutch is engaged?
it will stall because the ac compressor is seized and the motor is fighting to turn it so the engine stalls ...so I would have the ac compressor looked at it likely will require replacement... If he heater is set to defrost the ac compressor engages to blow cool air at the windshield to defog it ... try the heat in any position other then defrost and tell me if it still stalls