front fogs

[paulsa4]

Hi i have a b5 i have just got all the bits and now i wont to no the best way to wire them up especially the switch witch is a Audi one can any one Help please

[Pete@ECSTuning]

The fogs should go through the wiring harness at the head lights. You will need to use a volt meter and figure out which wire gets additional power when you switch the fog light button on. Then just splice into that wire, done!

[chris_r]

I've been working on fitting fogs in the bumper grilles and I came up with a good way to wire the new switch in. On mine there is no wiring at all inside the cabin so I've had to improvise a bit.

I got a forward fog light switch from an A8 off ebay. There aren't that many about and it cost me £8. Then I went down the my local scrap yard and found a B5. Fortunately, the one I found had been stripped and all the wiring on the dash was exposed. I found the yellow connector for the rear fog switch and cut it off. For good measure I also salvaged the other connectors for the heated rear screen and the beam adjustment too. Really, it's just the yellow one you want.

When you remove the rear fog switch in your car you will find this...



I've tested mine with a multimeter to determine which wire does what. Looking at the diagram above there are really only four important wires:

- +12v for the dash illumination.
- The dash illumination earth.
- +12v from the headlight switch.
- The earth for the headlight switch feed.

What you need to do is get some 5 amp wire and some insulated spade terminals. For the +12v for the dash illumination, the dash illumination earth and the +12v from the headlight switch you need to make one of these...



The idea is that you're connecting the new yellow connector to the existing one, but you're piggy backing off the wires to work the new switch. The earth for the headlight switch feed can connect directly from the new connector to the old as you will need a new earth running to your relay. Once you've made and fitted the harness just plug the rear fog switch into the new connector and tuck the whole lot into the dash.

The new female terminals will need to connect to your switch. The +12v for the dash illumination connects to terminal 1 on the switch, the dash illumination earth connects to terminal 2 and the +12v from the headlight switch connects to terminal 3. Terminal 4 needs to have a wire running from the switch into the engine bay and connecting to terminal 85 on a single pole normally open (SPNO) 30amp relay. Terminal 5 on the switch isn't used.

You can then earth terminal 86 on the relay, run a fused 17amp cable from the battery to terminal 30 on the relay and run another 17 amp cable from terminal 87 to the fogs themselves. Finally, connect each light in parallel with its own earth near it's final location.

Hey presto, job done.

[Pete@ECSTuning]

Awesome write up Chris, you should add this as DIY sticky somewhere! Many people don't have voltmeters so you saved a load of leg work.

[paulsa4]

Hi Chris thats awesone thanks for making it easey i will print it of so if any one els needs it

Once againe Thanks Paul

[chris_r]

You've saved yourself some cash. This was going to go on ebay as a PDF for £5 a pop.

[sluggs1]

Hi Chris

Can you help i am fitting fog lamps to my A4 b5 anyway i got one of these ring wiring kits with all the cables switch and relay in one fitted it all and was wanting rather than fitting the switch provided to fit a similar switch so as you have done i have got a spare A4 rear switch (the same as i have in the car) and the yellow connector behind it like you sourced from a scrapy anyway a few questions please-

1.with the Ring relay ter 86 is to the switch and 85 is to ground but you have it the other way round im confused.

2.I take it i wire my spare yellow connector to the same wires at the back of my rear fog switch,ter 1 to 1, ter 2 to 2,ter 5 to 5 and 6 to 6.

3 This would leave my ter 86 on my relay to go to ter 4 on my new switch but you say its to go to ter 85 on my relay

Can you help please

[chris_r]

Sorry it's been a long wait for a reply; I've not logged in in a good while.

Terminals 85 and 86 represent either side of the coil inside the relay. As far as I know it doesn't matter which is live and which is earth as either configuration will electrify the coil and activate the switch.

With regards to the yellow block, I'd check it with a multimeter and determine which wires to connect what to yourself. I know that doesn't sound like much in the way of help, but I've heard of different wire configurations and I really don't want you to damage anything unnecessarily.

Hope this helps.