S80 2006 No power to the rear defroster

Dalsim007 · Post by **Dalsim007** » 17 Sep 2018, 09:52

Hi all,
Trying to figure out the problem with my rear defroster. My car is a 2006 S80. When I hit the defroster button, it goes on, the side mirrors heat up fine but not the rear one.

I checked all 3 fuses in the trunk (2 20A ones, and the master 40A one). They are all good.
I checked on the C pillar on drivers side and the connector (like a 9v connector) doesn't show any power when I tested it.
I do not have any kind of codes in VIDA from this either.

By looking over at different place I see references to a possible relay that should be clicking in the trunk, but I can't seem to find any. It is my understanding that 2006 models do have a different connection type for the rear window heater though? I can only see a fuse box in the trunk?

Any help appreciated in trying to find out where the current could be cut.

Post by **RickHaleParker** » 17 Sep 2018, 16:54

No relay, power to the heating elements is through the Window antenna amplifier and the fuses are F37 & F38 in the trunk. The heating is controlled by the REM (Rear Electronic Module ).

Dalsim007 · Post by **Dalsim007** » 17 Sep 2018, 17:04

Thank you. My connectors are like the ones on item #18 on the top picture. From the vida replacement procedure of the rear window, it seems the power connector is the one that looks like a 9v battely plug (2 buttons side by side).

In my case, radio works fine so I guess the antenna module isn't dead? Fuses 37-38 are not burned, and the main fuse of 40A (#31) isnt burned either... Since Vida doesnt throw a code either with the Dice unit, is there something in particular I should look into? The whole REM module dead?

Post by **RickHaleParker** » 18 Sep 2018, 00:35

Have you inspected the rear window heating elements for opens?

In my case, radio works fine so I guess the antenna module isn't dead?
At least not completely. It clearly has more the one circuit in it. Heater circuit might be out.

it seems the power connector is the one that looks like a 9v battery plug
Inspect the rear window heating elements for opens.
Disconnect that plug and ohm out the window. If the Heating/Antenna elements are open the window would not heat but a radio signal can still be picked up on a open circuit. Also you watch the DC voltage across this plug as you switch the defroster on and off.

The whole REM module dead?
If whole REM module was dead, all your rear electronics would be dead, no light, no radio ect.