Heated Seat Not Working

[TymonZed4]

Hi.
I have a problem with passenger seat in my 2005 Z4.
Heating is not working, driver seat working properly.
First I checked both fuses and both are ok.
Then I connected to INPA and it shows error:
Right seat heating short circuit or open circuit
I ordered used switch panel but still not working.
Then I changed seats and passenger seat works fine on driver side but the one on passenger side still doesnt work.
Last thing I checked all the cables with multimeter and
didnt found any problems.
Does anyone had similar problem or have any idea what else can I check?
Thanks.

 

[Zulu4]

If both seats heat up when plugged into the driver's side, then it must be a wiring break on the passenger side supply wires.
If you've tested for voltage on the power wire then I'd hazard a guess that the earth wire (thick brown) has a break in it. (I guess if you have measured the voltage with the seat removed, you've now got an airbag light on).

 

[TymonZed4]

I checked wires for continuity. Unplugged central console panel and then checked for continuity.
INPA shows that the temperature sensor in seat is ok cause it shows right temperature.
I have no idea what else can I check.

 

[Zulu4]

Did you check the earth wire for continuity ? (This goes back to the bodywork rather than the centre console panel).
Perhaps you've got an intermittent break that only fails when the seats are in and connected with the wires in a certain position.

You could try running new wires to the seat. If you wanted to stick to BMW parts you can use Wiring Set 61116930656 (E46 loom).

 

[TymonZed4]

I have checked also earth and its ok but i cannot check if earth is good or poor. I will try with another wire next week and will see if its change anything because it might be last thing to check. Multimeter shows no short circut or break but earth may be weak.