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Fog light not working

Posted: Thu 07 Dec, 2017 10:50 am
by Don-vic
The drivers side fog light on my 300te has stopped working. Globe is fine. Have put test light on connection, no power. Have checked fuses, all fine. Presume switch is ok as the left side works. Any suggestions before I start a serious investigation ..

Re: Fog light not working

Posted: Thu 07 Dec, 2017 11:58 am
by Christo C
On my car the one fuse (F4) feeds both fog lights so as you surmise the fuse is ok - feed from fuse runs to fog switch (two contacts, part of the lighting Combination switch) then two wires run to the Light Control Unit (largest module in the bay behind the fusebox) then two separate wires to front L & R fog lights;
So the problem could be
- the lighting Combination switch - less likely, as I'm thinking one of the two wires is for Front Foglamps, and the other is for Rear Foglamp (the switch has two pull-out positions).
- the Light Control Unit module
- wiring fault.
If the other lamps in that headlight unit work then you can probably rule out a bad earth connection.