Before you end up going this route, I should mention it doesn't work completely correctly the way I have it wired into the OEM heated seat wiring. There is only one heat setting, and after about 5 minutes, the heater turns off automatically.

There appears to be some kind of fail-safe built into the OEM circuitry that turns it off. When I wired this, I replaced the thermistor with a regular resistor in the circuit, and I think this is probably why it shuts itself off. It may work correctly if you keep the thermistor, but I can't say for sure. I might try it some day...

Are you looking to fix broken seat heaters, or install from scratch?

 

Yikes.

I am looking to fix broken seat heaters; my driver's side sometimes can stay on for 30 seconds at the most lol but otherwise when I hit the button, it's just on for a nanosecond. I probably just have to check for corroded or exposed wires, but it's already in the 30's in chicago ( ._.)

 

Interesting problem. It could be a bad connection in the seats. With mine, it was pretty obvious this was the problem because the seat cover smoking/burning!

Does the seat start getting hot at all when the light stays on for 30 seconds?

Another quick check you could do is pull the heated seat and mirror switch piece out (find something thin to stick under and it will just pop up) and swap the left and right heated seat button connectors. If the problem switches seats, its the switch/circuitry, not the seats.