# Heated Seat Temerature Sensor causing no-heat on one seat?



## van-couver_93EV (Apr 7, 2008)

Has anyone had this happen or if you are familiar with how the Seat Temperature Sensor (there's one in each seat) works you may know the answer?

I am trying to figure out why the driver's heated seat doesn't work (passenger side does work) in my sister's 2000 Jetta TDI (cloth seats). I think it might be the seat temperature sensor telling the controller/switch that the seat is smokin' hot, so the controller doesn't energize the seat heater.

I have taken these measurements from the back of the switch/controllers:
- Both sides have 12v supply power where they should (fuses are OK)
- resistance through driver's seat heater is ~17 ohms
- resistance through passenger's seat heater is ~16.6 ohms. I think the seat heaters are OK.
- resistance through the driver's seat temperature sensor is 950 Mega-ohms
- resistance through the passenger side seat temperature sensor is 10 to 16 Mega Ohms (lower end of the range if the heater is on for a bit)
- voltage on the driver's seat heater is 0.
- voltage on the passenger seat heater is 12v.
- voltage on the driver's seat temperature sensor is 5v (plug under seat disconnected) and 4.9v (plug under seat connected). So the 950 Mega-ohm resistance is pretty much an open circuit.
- voltage on the passenger seat temperature sensor is ~1.5 volts.

I swapped the controllers/switches and got the same results.

Does anybody know where the seat temperature sensor is located (bottom or back)? Anybody had to replace this?

thanks,

Ian Mothersill
Vancouver, Canada


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## van-couver_93EV (Apr 7, 2008)

*update - heated driver's seat*

I ran a wire from the seat temperature control on the passenger side to the driver's side, and the driver's seat heater works now.


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