Rear Defog, Heater Fan problems.

My Jimmy's heater stopped working. I wired the fan directly to the battery and she fires up. Probably heater resister, so I was told. What bothers me is the same time, I lost my rear defog, Airconditioning (Winter so I don't know for sure) When fan is hooked direct, the hot air comes out but can't adjust temperature. Can't spread heat to defog, it only comes out the vents. Can't select the circulation type (Inside or outside air). Had it flushed recently. Worked great after the flush. Battery died for about a week, had it in the garage. Would the control unit within the truck have gone bad? Does something need to be reset in the computer? I checked and changed all fuses.

Any help would be great seeing as it is Minus 20 for the last two weeks.

Pross

What year Jimmy?