2008 volvo S40 D5 front seat problem
 

I now own a 2008 S40 D5, tried to use the heated seat and nothing happened, I checked both fuses and fine, wiring under the seats are fine too, any other ideas? Or how to check what the fault is? Not a mechanic but a fast leather

It might be the little module under the seat. I had the same problem with my V50 and it was caused by that. When it happened my drivers side temperature control also wasn't working (it was stuck on the lowest setting and let's just say that it wasn't ideal in the middle of the winter :) ). They are all connected to eachother with LIN bus, so one caused the other not to work. I removed the passenger seat module and connected it to the drivers seat to check first.

If it's not the case, then it might be the element itself inside the seat.