Seat heating partially inop
 

On the drivers side seat, only the bottom part of the seat gets warm, but not the backrest part. The passenger side works great. Is this a common or easy fix?

Usually the problem is with the seat cushion, not the back rest.
Take a look under your seat just in case the connector for the backrest is unplugged. There is a big rectangular yellow plug, from that plug, a cable is goind toward the rear of the seat, up to the cushion. On its way toward the back, there is a split and another cable (smaller) goes to the backrest. There is a plug there that could have been unpluged by objects moving under the seat.
If you have a multimeter, you could unplug that connector and measure the resistance of the backrest heating element. It should be around 3.5 - 4 ohms.

I'm in the process of repairing my cushion heater, so it is fresh in my memory.