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I searched the seat heat threads but find no mention of a fuse. Is there a fuse for the passenger seat heater or is this powered by the 20 amp fuse for the seat module circuit? I bought the car two weeks ago with a missing seat mod, and the used box I got on Ebay has everything working again except for the seat heater. Does this require programming? The passenger heat switch does not light up when pressed but the drivers side works and lights as it should. Any suggestions for diagnosis are very much appreciated.
Just looked at schematic. Need to know what kind of seat we are talking about: memory options present or not. 3 way movement? 5 way movement?
No there is not a separate fuse for the heater.
The O or orange wire out of passenger seat control module provides power to seat heater, squab heater connected in series with red wire to squab heater. This goes to B black shared ground wire. Lumbar pump shares this ground.
Never had this problem but have the Electrical Guide excerpt
Jagophile,
I never had your problem (no nee for seat heaters in 110degF weather in Bahrain), but here's this excerpt from my electrical guide for my MY may shed some light.
Looking at it, the centre console switch goes to the BPM, then the seat control module and then to the seat heating elements. Different fuses for each module, so do you have other any issues too?
First step is to swap driver and passenger side control modules and see what happens in terms of heater. Normally, the fault follows the module. The loss of heater function is one of the symptoms of these worn outer edge tracks on the circuit board, so you should look into fixing the module circuit board (either yourself, or get it serviced). To my knowledge (I have no direct experience with this aspect), loss of heater is also a sign the part needs to be "programmed" to the ECU. This is generally why folks tend to repair modules instead of replacing them as used parts come with the same design flaw, and may need programming on top of that. You situation is clearly different as the module was outright missing. I'd say if the new module ends up being the problem, open the lid and inspect the circuit board along the edges. Check for breaks, and re-solder shunt wires to repair.
Replaced seat module but no seat heat
