[KevinH1990]

If you really want to understand how the heated seats in a 986 work, read Dennis Vogel's article on retrofitting them: Dennis Vogel: Projects - Boxster Heated Seats

Based on using the instructions to retrofit seats in my car, the problem is most likely one of the following:

1. Damaged relay under the seat- relatively simple to replace
2. Damaged heating element in the seat - Likely to require removal of the leather seat cover to repair.
3. Damaged wiring.
4. Damaged switch.

You can check whether it is a defective switch or relay by swapping the switch and relay from the side that works into the side that doesn't. Start by swapping the switch since the only way to access the relay is to remove the seat.

If you have to remove the seat, you can check the wiring under the seat when you have it out.

If it turns out to be the heating elements, you have two options. (1) Swap out the heated foam rubber pad. Dennis Vogel provides the part number, but the price has increased since he wrote his instructions. (2) Wire a heating pad element from an aftermarket kit into the Porsche wiring. I have not done this myself, so you are on your own. Removing and replacing the leather seat covers requires skill with "hog rings'. Check YouTube for instructional videos. Dennis states that he used an upholsterer.

Good luck with your repairs.