740 rear fogs. Confused

[Bartman]

Been trying to get my rear fog lights working in order to get through the mot but as i'm a bit of a novice, i'm out of ideas.
Neither of the lights are working and the switch does not light up.
On checking i found that the o/s bulb had blown so i replaced both bulbs and checked the fuse but still nothing. I have now checked the switch by swapping it with the rear de-mister switch, so now i know that there is nothing wrong with the switch. The wires that i can see at both ends look to be fine, so now i am getting a little confused by it all.

Any ideas???

Thanks

[Clan]

so the switch doesnt light up .. that indicates the fault is at the front end .. did you have dipped headlamp beam on when you were testing ? Do you have a towbar by any chance?

[Bartman]

Tried it with sidelights, dipped headlights and full beam, but no joy. Yes it has a towbar and the electrics on it are fine. Could the towbar be an issue?

[Clan]

yes the towbar socket could be the problem , together with a faulty bulb in the switch .
The fog light wiring goes through a crude switch in the 7 pin socket and bacl out to the rear fog light , the switch can corrode , a new socket with built in fog light switch will cure it . the switch cuts off the fog light when a caravan is plugged in ..

A bit of work witha test light should quickly locate the fault starting at the fog light switch ..

[Bartman]

Thanks. I'll give that a try and let you know how i get on.

[Bartman]

So after removing the towbar electrics and spending the best part of six hours stripping the back end of the car and the dashboard, I discovered that the rear fogs use 2 fuses, and one of them wasn't even there.

DOH!!!!!!