Rear fog light in bumper wont work

[Gavin Waddell 18]

Like the title my fog light in my rear bumper doesn't work. And the dash switch doesnt illuminate

I have checked the wiring all the way back to the fuse board and its good.

.I worked out that normally when tou switch the lights on it should illuminate the switch, the heated rear window and the hazards light up but not the fog light?

I then checked the wiring from the light stalk to the switch and its good apart from that there is no power to the thick brown wire Number 155? Which im guessing is what powers the fog light and now im stuck as what to test

 

 

Gavin

[Gohn 68]

yeah the buttons should illuminate on low when you turn your lights on

Hazard button, fog light, rear demister and A/C (if you have it)

the fog light button will only illuminate properly when depressed, and only when you DONT have headlights on HIGH BEAM

(suppose its a kind of safety feature to ensure drivers dont use high beam when its foggy, as it makes vision worse apparently)

oh and as always, check your rear earth

Edited October 21, 2023 by Gohn

[welshpug 1,657]

don't go by what the light on the button is doing, they're often faulty.

 

if you have no power at the switch then work backwards in the circuit, 151 is the wire TO the fog lamp, goes through F10 to the nearside lamp cluster then to the fog lamp.

 

fog lamp feed is wire 150, from the main combination switch, on the diagram shows the same terminal as dipped beam.

 

there is no wire 155 on the circuit.   wire 55E is the dashboard illumination, M150 is the earth for the switch

[welshpug 1,657]

most common issue is the terminals in the plug on the back of the fog lamp corroding, earth circuit is shared with the whole rear lamps.

[Gavin Waddell 18]

When i plug the the switch into the heated rear window it illumintes? Im going to check the brown wire 150 like you said, i found this diagram.so going to check its connections at the fuse board plugs.

[Gavin Waddell 18]

ÔProblem fixed, it was a dodgy stalk, put a spare one on and fog light switch illuminates as well as the fog light, easy fix.