No fog lights help for mot please

[mospin1]

Second post since joining and this is the most important to fix and has been driving me insane for months and with the mot nearing it's now on the to do list.

Car is a 1999 audi a4 b5 1.8t sport

Problem. No fog lights front or rear

What I've checked., bulbs are fine, fuses are fine, changed the relay 397 I assume that's. Correct.

What I've noticed is the two switches on the dash that normally light up green when pressed no longer do.

I'm not electrical minded or know my way around an audi or where to start so if it's possible someone knows the problem or can point me in the right direction please help.

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[mospin1]

And if anyone can tell me what the liitle 4pin black thin plug is for inside the headlights as its not connected to anything?

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[FrenchAudi]

It's possible that the switches are faulty, or have been disconnected. You can check the connectors on the back of the switches are in place if you remove them from the panel.

To remove them, press down on the lower part of the switch to tilt it slightly, and lever it out with a small screwdriver or a flat plastic tool.
This will remove the cover. The switch itself can then be removed, together with the plug on the back, by gripping the bottom edge with a pair of pliers and pulling it out.

This is a photo of the instructions from my Bentley repair manual. It's too big to get it into my scanner.P1010001.jpg

[mospin1]

The switches where working some time ago forget to mention just before this happened we had a heavy rain fall that filled the bulkhead and all the lights blew up front.

I had to change all the bulbs but not the fog bulbs as they were fine but ever since they have not worked. And I've changed bulbs, fuse and Relays but the green indicator light on the switches still don't work.

The diagram you have posted isn't for my car as I'm sure you have to remove the whole dash center to get the buttons out.

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[mospin1]

Still can't get this figured out or know where to start.

I've checked the relay again and opened it up and that's fine.

Bulbs are fine

Buttons I've removed and they seem fine can't find nothing out off place

But still have no rear or front fog lights

Did manage to fix the fuse on the amp that kept blowing which was the amp blown but could really do with some help figuring this out for the mot or if there's a way to rewire them

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[mospin1]

Right I've now changed the relay, buttons, fuse and bulbs and still no joy with front and rear fogs not working, any ideas what to look for now mot is creeping closer and need the rear one working

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[Scott K]

If the switches aren't illuminating, it means they aren't getting power. Need to fault find that.

[mospin1]

They illuminate when lights are on with the stock orange but when pressed they green indicator lights don't light up, I've check that I'm getting 12v at the fuse but no idea which wires to check at the relay?

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[mospin1]

I'm still having this problem off no fog lights front and rear.

I've changed

Fog light switches
Fuse
Relay
Bulbs
And checked the wiring for power is there anything else I should check for

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[VAG-Abound]

Looking at the wiring diagrams the button lights and fog lamps for are all fed from the control relay you've replaced. Was it a new one that you used? It still seems like the most likely single component to get the results you're seeing.

Number plate bulbs and glove box also seem to run off of there. Are they working OK (presumably yes if you passed MOT)?

After that it'd be down to checking voltages and resistances at various points with a multimeter or at least "bulb on a wire", but not sure from post 1 if you want to get into that.

If you want to test switch module it looks like pin 3 to ground, 1 for "off" light, 2 for "on" light, and switch action between 4 & 6.

Removing the relay you should have good path to earth from socket point 6, and 12V supply to 9 and 14 with ignition in various positions.

To test things without high current draw, removing the actual fog bulbs then putting 12V (from socket on relay or cigarette socket using a plug from Halfords / eBay?) to relay socket 2 or 5 should light dash indicators for rear and front respectively. If feeling more adventurous then a 1.5mm wire or larger (I'd use 2.5mm ) should allow you to actually light fog lamps via same pins. Pin 4 should light number plate. If that gets things lighting up it's again suggesting control module isn't getting 12V to those points. If not then earth points may be suspect, but unlikely for both front and rear without other things failing,