I have a S4 with heated front seats, and am sure both were working when I first got the car, but now the passenger seat refuses to heat up.

I thought it might be something I did, as I took the passenger seat out recently when trying to find somewhere to stick the bluetooth module, but gave up and stashed it behind dash like everyone else!

I have just had seat out again, and unplugged and replugged everything to see if I could cure it, but still no joy.

Ended up getting the laptop out, and with VCDS you can see the seat temperatures in the measuring blocks of the climate unit, and it was saying the drivers seat was at 20.1degC, but passenger seat was at 102.9degC, so it is obviously thinking its baking hot already and wont send power to it.

Is it common to have problems with the temp sender inside the seat, or is it likely to be something else, like will a short or open circuit between seat and climate unit give me a temp of 102.9degC?

I had a look at the wiring on the seat whilst it was out, and assume the temp sender is only in with the element for the base, as that had a 3 pin plug, whereas the plug for the backrest element was only 2 pin so must just be a heater with no sender.

Any help greatly appreciated.