Fog lights and Main Beam

[Nick-C]

Does anyone know if it is possible to code the fog lights to work with main beam and not loosing any of the functionality of the fogs/cornering lights using vcds. Thanks

 

[Loz]

I think that is the default option? There is a vcds option to prevent fogs with main beam that is not ticked on mine.

 

[Nick-C]

Thanks for the reply, I know you can disable the fog when you put main beam on, I want the opposite. I have just upgraded my bulbs in the H4 headlights and I find the lights would be acceptable if when going to main beam the fogs came on as it would help fill in the light pattern where the dipped beam was if you get what I mean! It would in essence be acting a little like the H7 units where both dipped and main beam can be on at the same time. Cheers

 

[Loz]

Are you saying you want the fogs to come on automatically with main beam without pulling switch out?
Or
If you have pulled the switch out for fogs they are going out when you switch to main beam?

 

[Nick-C]

Sorry just read my last post and realised it wasn’t clear, yes I want the fogs to come on automatically when I put main beam on. Cheers

 

[Loz]

Right, with you now.. no is the answer as far a coding goes, but possibly with a bit of a wiring mod I suppose, to feed the front fog switch feed with the feed from the high beam, but it won’t pass an mot like that..

 

[Nick-C]

Cheers, done what you describe on older cars using a relay. Would be worried to do the same on the T6 for fear of messing the canbus up. (Reverse feeding the fog light circuit). Many thanks for your help!

 

[Loz]

Not so risky as the bcu does all the switching, a feed with a diode to stop reversal might be all thats needed, and its all in and around the steering column so would be simple to test I suppose. Have a look at the circuit diagrams in the download area.
The switches are not on the can bus as that only goes between the modules, the switches etc are just fused feeds into the bcu.

 

[Nick-C]

So if I put a diode in the feed from the main beam +ve so it can feed the fog light switch this will turn the fogs on, but turning the fogs on wont back feed the main beam? I think I get what you mean and it’s worth a try. Is there nothing to damage in the bcu? Like bulb failure stuff etc? Cheers

 

[Loz]

So if I put a diode in the feed from the main beam +ve so it can feed the fog light switch this will turn the fogs on, but turning the fogs on wont back feed the main beam? I think I get what you mean and it’s worth a try. Is there nothing to damage in the bcu? Like bulb failure stuff etc? Cheers

Not the main beam lamp output positive, the main beam switch output to bcu line, I’ll try and find the right page on the wiring diagram when I get to my desk in the morning..

@Pauly what do you think, have you tried this?

 

[Nick-C]

Cheers, really appreciated

 

[Pauly]

Not something I have played with but a relay triggered by the high beam switch feeding the wire for fog lights from light switch should work fine just need to see if it's a switched +ve or -ve from switch to BCM

 

[Loz]

How about a diode between white/green on here;


To white/red on here?

 

[Loz]

Now that reminds me, on the series 1 Touareg there was a vcds mod called the 6 gun salute that put all lights on when you flashed the headlights, dip, main and fog...

 

[Oldrat]

Fog lights are legally only allowed to be use in poor weather conditions, nowt in the regs about darkness being poor weather

 

[Craigsom]

Now that reminds me, on the series 1 Touareg there was a vcds mod called the 6 gun salute that put all lights on when you flashed the headlights, dip, main and fog...

now that's something I would want

 

[Nick-C]

Thanks Guys!! I will have a look this weekend, if it works I will post a write up

 

[Loz]

Been giving it some more thought, I think you may need to use the main beam output with a relay as I think the stalk swith is only a momentary action and the bcu latches on the output.

But it should be easy to test with a meter. Here are the headlight outputs you can pick them up leaving the BCU

 

[DaveyB]

Fog lights are legally only allowed to be use in poor weather conditions, nowt in the regs about darkness being poor weather

Totally agree. Simple answer is it is illegal from a road traffic act perspective.

 

[Loz]

I’m not defending it, its just a technical challenge to me.
You wouln’t use main beam with other traffic around so I don’t see any harm in it personally and plenty of drivers have fog lights on full time (which is annoying).