Right, this is driving me bonkers! I cannot find any wiring diagram clues anywhere I've tried searching other posts mentioning the reverse light conversion, but no wiring is mentioned for the UKDM switch configuration.

I've got most of the wiring done, 2 earths and 2 lives when lights on, the fifth one is a problem one.

The one I'm using from my front fog switch only come live when the switch is activated, and splicing into this obviously causes the rear to become active at the same time. Not a problem thinks I, it'll probably get through the MOT until I can work it out , but, and this is the big but, no lighty up at the bulb end!?! I've got 12v approx registering at the bulb holder and new bulbs, but nada light!

Is a relay going to be required?

(I should point out it's using 582 reverse bulbs 12v21w )

I don't know whether I've shown you this before, but this shows the wiring for my fog switch.
One of the red wires goes to the under dash fuse box, the other is spliced into the reverse light.
I can't remember where the black one goes.

If I get a chance I'll try and get a photo of the fuse box and light cluster.
It won't be today as my phone is not charged and I'm off to work in a minute.

The 5G switch has 5 wires (if I remember correctly):

2 Black
2 Red
1 Orange

Just like the front fog light switch.

Edit - Is that what the back of your switch has?

5th gen'?

This info is for the front fogs, but I would bet that the switch is the same. You can use the diagram for hint on how to wire the rear fog. Although it depends if you are using a relay, Personally I would just to be safe.





From the top:
Black = Earth
Orange = Goes to relay or staright to the rear fog
Red with black stripe #1 = Takes power from head lights OR a corrosponding wire from a neighbouring switch (This is to illuminate the fog light icon so you can see the button in the dark)
Red with black stripe #2 = Takes power from the ignition (This is to illuminate little green light to say the rear fog has been activated)
Black = Earth


Is this any help?

Cheers, for that , but strangely, those aren't colours for my front fog switch

Here's the wiring that came with my rear switch

Yup I have found a pic of what my rear fog switch look like:




Do you have a multimeter or test lamp to see what all the wires from the switch are meant to do?

Edit - Do you remember the guy in the US who did the dual rear fog mod on his USDM car? I have been trying to find that thread, there may be clues in it.

Edit 2 - Found it but he didnt use an OEM rear switch.

I'll try and get a piccy up of my botch and make a diagram of my current connections I think I might temporarily end up with a 3 pole illuminated switch just to get it through it's MOT