An engine usually has a higher idle speed when the ac is running. If the high speed idle does not operate then the ac will cause the engine to stall.
check clutch fan
Be sure the cooling fans are functioning when the ac is running.
If coolant is up to proper level and cooling fans are working - should not overheat
It's purpose at that time is to keep air moving over the AC condenser. The AC condenser is located in front of the radiator. The high pressure side of the AC would overheat or would develop too high a pressure if it were not cooled by airflow when the AC is functioning.
The high speed blower relay is located on the engine bulkhead bracket next to the blower motor. === ===
no
If the engine is overheating, running the ac will make it overheat faster. The ac only cools the inside of the car, it actually adds heat under the hood.
yes
The idle speed control solenoid controls the idle of the engine when the air conditioning is engaged. Since the ac pump draws down the engine idle the solenoid increase the idle when the ac is on.
A car is more likely to overheat with the AC on because the AC radiator is in front of the cars radiator expelling heat. so if the engines cooling system is operating near capacity for some reason the heat coming from the AC can be just enough to tip it over the edge. The engine also has to work a Little harder while the Ac is running which would not help either.
The high speed relay switch may be faulty.