Cavalier 1.7td fog lights

Hi

My Cavalier failed MOT today as the fog lights weren't working. I have
checked the bulbs and fuse which are ok.

The car was fitted with 12n tow bar electrics in 1993. I have a multimeter
and 12v testing bulb and a Haynes Manual with wiring diagram. Is there a
web site that can guide me through what tests and in what order I can do to
identify the fault?

Thank you

Mick

 

Does your fog light switch light up to show they are on? If yes just follow
your tow bar wiring up from your socket into the boot. You may find that a
relay was put in to stop your fog lights working when the bar is in use and
it has failed.

 

Might be a device in the lighting socket on your towing set-up which cuts
power to your car fog-lighrs or redirects it to your caravan lights or
somesuch.

Have a look at the socket - a few years of damp. salt and corroision can
cause all sorts of problems (They get all the muck that you get over the
back of your car, but more so!.

Lots of wd40 on the connector pins might help, also there might be a small
mechanical device (a pin that pushes in when you plug-in the cvan lights)
that is stuck and might need freeing-up.

It might help to take the socket off the car and have a look at the wiring
inside it - a wire may have come loose or more likley corroded through.

If in doubt, simply pop to your local caravan place, show them the socket,
ask them to sell you a new one, then fit it - or ask them to - this might
effect a cure. Or even disable the fog light cable/device just to get you
through the MOT!

 

Still having probs with NO fog lights.....It's a 92 Cav and there are no
front fog lights fitted. There is no current to number 27 fuse. I have
tried to understand the Haynes Manual wiring diagram..( first one I've
read ) but can't see what route the power takes from the battery.i.e. colour
of wire, does it go through any other components
Anyone out there help a drongo?
Mick