I read in the IVA manual and from other posted on here that the rear fogs must only be able to be turned on if the dipped headlights or main beam are switched on. It must not be able to turn on with just the sidelights.

I have fitted a very nice audi/VW rotary light switch into my car and this switch allows the rear fogs to come on with just sidelights on. It will also work on dipped and main beam. My daily driver Audi A8 uses the same switch and that allows the rear fogs to come on with front side lights. Surely this is ok? It wont allow you to put front or rear fogs on without switching the light switch to the first setting which in this case is sidelights.


So question is, would the IVA tester allow this? I will be towing my car with the audi A8 to the test so I can show him if needed.

Car is basically finished, I don't want to have to change the wiring for this if I can help it. Does the tester try all the lights etc or will I be the one sat in the car and he will ask to turn on light and so on??

Depends !!!!

The new regulations say something like - if fog with sidelights, there must be some sort of warning when the keys are removed...
This is to prevent you from forgetting to switch them off when getting into the car after parking up with the side lights on.
You know how irritating it is following someone with fog lights on when driving on a clear night.

The old design of fog with main / dip only as in old cars - ie sierra, works OK. Just passed 31st March like that at Yeading.
Mind you - you can still end up leaving the fogs on with this setup but at least it is a legal setup for 'old cars'......

He checked the lights with me doing the switches. If he asked me to select certain lights, I did as I was told.
If you did as you want, maybe he would be upset and dig deeper if you know what I mean.
If the tester does it himself with mirrors - the same as some MOT stations, you would fail I am sure.

If you want to keep you specific controls, just fit a relay powered by the main/dip power to prevent the fog light from
coming on in the sidelight mode.

In your audi front fogs come on first and then rears. Fronts can come on with sides. Rears can come on if front fogs are lit. Assuming you don't have front fogs fitted, you need to change wiring in order to use that switch.

Rear fog coming on with side lights was one of my fails.

Passed on Tuesday wired to dipped headlights.

Cheers
Paul G