Is it normal for ac compressor to come on and go off with the heater 2002 dodge ram?

No, it's not normal for the AC compressor to cycle on and off with the heater running in a 2002 Dodge Ram (or any vehicle for that matter). The AC compressor is part of the air conditioning system, and should only operate when the AC is turned on. The heater uses a completely separate system.

If your AC compressor is engaging with the heater on, there's a problem with the system's controls or wiring. This could be caused by:

* Faulty blend door actuator: This component controls the mix of hot and cold air. A malfunction could cause the system to think AC is needed even when the heater is selected.

* Wiring issue: A short circuit or faulty wiring harness could be sending incorrect signals to the compressor clutch.

* Control module problem: The vehicle's climate control module might be malfunctioning, sending incorrect signals to the compressor.

* Low refrigerant: While less likely to cause it to cycle *with* the heater, extremely low refrigerant *could* cause erratic behavior.

You should take your 2002 Dodge Ram to a qualified mechanic to diagnose and repair the issue. Continuing to run the AC compressor unnecessarily will put extra strain on the system and could lead to further damage.