When the heater is on and I switch from vent to defroster AC pump comes on is This normal?

Yes that's normal operation.. Air conditioning is a great dehumidifier plus it helps to 'exercise' the system in cooler weather... However the air temperature from heater should remain the same, *otherwise it would not melt ice (frost) from the windshield* and that's the whole point! .. Switch to defrost and let it run for a few minutes then check air temperature from defroster vents.

Hi Joe, Yes Joe on some vehicles this is normal cold air clears up the fogging windows. The reason for this is if they use hot air there is a chance due to temperature changes that it might crack the window. Normally it is routed to the window front dash vents not to passenger compartment. Hope this helps if there are any other concerns feel free to give us a call. Sincerely Ultimate Performance Team.