Answer to "Why doesn’t the air in the backseat come on?"I would start with the fuses. There is a 30 amp fuse in the fuse block under the hood. Another fuse is in the interior panel. I believe it is titled IGN 3. If those are not the issue you may have to access the blower motor in the rear of the SUV.
Answer to "magnum 4wd automatic tranny won't shift"I would have the speed sensor checked.