Rear Fog Light Wireing.

[JonLeeper]

The rear fogs were another fail item for me but I have changed the bulbs, fuze and tried tried to chase the wiring down with my multimeter but all to no avail.  I have power to the dashboard switch and the switch lights when turned on but nothing else appears to happen. 

I have removed the dashboard switch from the loom and am faced with a white connector block with 5 terminals.  Two across the top, two in the middle and one at the base.  With the ignition off I have 12 v across the top two terminals and nothing else.  With the ignition on and the lights on I gain 12 v across the top to bottom pins.  The middle two pins don't alter.  The dashboard switch has three positions and I am guessing that they are for front and rear fogs in some relationship.  Can anyone tell me which pins should activate the rear fogs and I can jump the loom block to check if the rest of the circit works. 

Many thanks,

jon

[rubjonny]

where is the hazard switch, dash or column?

[JonLeeper]

Hazzard switch is on the dash between the fog and the heated rear screen.

[rubjonny]

right, 1st click on switch is front fogs, 2nd is front + rear fogs

pinout is:
pin 83 - grey/yellow - switch power
pin 83a - white/yellow - front fog output
pin 83b - grey/white - rear fog output
pin 31 - brown - earth
pin 58b - blue/grey - dash lights feed

pin 83 is fed from pin B/20 on the rear of the fusebox, or possibly direct from the headlight switch.  There may be a jumper plug from the light switch that pushes into the front fog relay socket?
The front fog wire runs to pin B/16, and the rear fog wire runs to pin B/2.  Then last of all the wire to the rear fog light comes from pin E/10.  Check my fusebox FAQ for more information, its in the MK2 how2 section. You need to look at the pre/90 wiring information

I take it you checked the rear fog fuse clipped above the fusebox hasn't blown?

[JonLeeper]

Many thanks for that.  Yes I have checked all of the fuses that could possibly be assiciated with the fogs, including the single one up by the relays.  I have power to two pins, 83 and 58b I suspect, and did try jumping across the multiplug from 83 to 83a & 83b.  No joy on the lights so I tried to measure a voltage across the fuse but did not get anything.  I am assuming that the wiring goes from the switch to the fuse and then through to the rear loom.  I have never meadled in car wiring before and am somewhat scared by the sheer number of wires in the loom, there are just thousands going all over the shop!  Also trying to work on your own holding a multimeter and controting yourself under the dash is not the easiest of occupations!

I order to try and bottom this out is it possible to get a 12v feed and jump across the fuse box to see if the circuit is complete from there to the lights?

[rubjonny]

yeah it goes 83b -> fuse -> fusebox -> rear light

1st thing I'd do is find a 12v feed and pop it into pin 83b of the fog switch, then check for 12v at the fuse. If there is voltage here and the lights come on you know the wiring from the switch is ok, and either the switch or the wiring to the switch is at fault. 
If this doesnt work then you know the issue lies between pin 83b and the fuse. There is a massive multiplug close to the fusebox where all the dash wires run thru, check this for any wire damage and also its worth unplugging it and checking the terminals for corrosion.

Its much easier to remove the dash under tray if you havent already, just a few screws hold it on

[JonLeeper]

The dash has already come out, along with most of the interior!  The seats are horrible cheap buckets, soon to go, so all of the wiring is exposed.  I'll try feding 12v through the 83b pin tonight. 

Many thanks for all your help,

Jon

[JonLeeper]

Well I jumped the dashboard switch and there was nothing at the fuse.  I traced the wire through and found a neatly severed cut!  That ha been patched up and I had power at the fuse but still no lights!  I then followed the wires back from the fusebox and found another neat cut, this time with one of the ends taped up!  That now has a temporary fix as they had physically chopped a piece out of the wire so that I couldn't make the ends meet, and the offside fog light lit!  The nearside is still dead but for the MOT I only need the offside one.  I then refitted the switch and found that it too was dead!  That's two separate cuts to the loom and a dead switch, someone really did not want the fog lights working ever again!  I will have to get myself a proper electrical repair kit to make the joins more permanent and get a new switch but for now I have found the problem and can start on the next fault, CV Boot!

Many thanks for all your help rubjonny,

Jon

Edited for spooling mistakes!

[rubjonny]

nice!  there should only be 1 foglight on a MK2, the othewr side has no wiring, bulb or hole. if you wanted to you could knock out the blanking hole and fit a bulb, then run a wire from the driver bulb try to the passenger side

[JonLeeper]

Both of the "bulb boxes" on the back of my Mk2 are identical!  The same number and position of bulb holes so I am not sure if the nearside has been changed in the past.  I have fitted a new bulb on that side but it will only be a spare for any of the others that break!

Which type of connectors are the best for fixing this type of thing?  I was thinking that I would get a generic Halfrauds type multi-part set that allows me to fit spade type connectors and then cover the joint in some electrical tape and zip tie the repair to the original loom to prevent any movement.  Any recomendations or suggestions for kits?