Has anyone added heated seats to their truck that didn't come with them? I found the heaters but didn't see the switches listed on the parts website. Also wondering if the wiring is already there in the seat harnesses. I have power drivers seat.

 

I think the stock seats in that era had a brain box, too, and the switches are multiplexed. The module would blink the lights in various ways to indicate open heater circuit, short in heater circuit, or the temp sensor out of range.

I think for adding heated seats, it might be better to go with one of the aftermarket kits. Geno's I think sells some.

 

Go aftermarket, easier to retro, and cheaper. Like Jeff states, there is a controller, and various wiring, it recieves power off of the power mirror circuit.