Is this a problem or normal?

2002 Ford Ranger XLT extra/extended cab
3.0 v6
171661 miles.

Any time I turn on the A/C or heater, I hear something clicking and the engine or transmission revs for a few seconds. if I have the truck in [D]rive and I have foot on the brakes, the truck tries to move forward as if your pushing the gas while the Em. brakes are on. If I have the truck in [P] park with the A/C or heater on, it makes the clicking noise and the RPM odometer moves up to the 1 or 1 1/2.
Is there a problem here?

nyerhowho2015-02-07T14:11:48Z

Problem

Rick2015-02-07T14:10:56Z

Forgot to add , if I have the A/C or heater Off. It doesn't make the clicking or tries to move forward...