Headlight Switch Fail

[Littleblackflash]

My headlights are on all the time. It doesn't matter which position I move the switch to, they are always on. My front and rear fog lights don't work.
VCDS shows no errors, but strangely also shows no errors when the switch is disconnected. All my lights work when activating them using VCDS.

Unfortunately my MOT is due this month and even through they are friendly with my race cars which never go on the road, I'm sure they won't turn a blind eye to this.

Any thought? I may swap the switch with the one from my mum's UP! and see if that fixes it.

 

[Dellmassive]

Have you tried a power reset?

Full Van Ecu Reset (capacitive Discharge) -- How I Done It --


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[Littleblackflash]

Thanks, I guess it's worth a try.

 

[Dellmassive]

Lights are BCM controlled, light switch is a BCM input.

So it's worth a go first.

 

[Littleblackflash]

Swapping the switch for my mum's UP! didn't work. I've only Dell Massive's idea left.

The BCM is controlling the light ok because you can test them with VDML. It's the switch to the BCM which isn't doing anything.

Strange how the headlight are always on.

 

[Pauly]

if you unplug the switch the headlights come on, I always figured it was a fail safe type setup

 

[Littleblackflash]

I found the wiring diagram in the downloads. The switch LED lights are fed by 1 fuse, but the switch feed is from a separate fuse.

Recently I blew the fuse for the central locking and I'm wondering if I removed the headlight fuse when looking for the blown one, and then not insert it back in the same slot. It is awkward doing it at an angle.

 

[Pauly]

That’s a good shoot, the controls are normally fed from a different circuit than the equipment being controlled

 

[Dellmassive]

Lol.... if it's a fuse issue I bet your be kicking yourself and patting yourself on the back at the same time.....

 

[Littleblackflash]

Kicking and Patting

Fuse was in the wrong slot. I kept moving one until the lights came back on, but...

Set to Auto, the side lights and main lights are on, which is expected when dark. But when I select the side lights, the mains stay on. Is this normal? I would of thought only the little side lights should be on.

Fog lights and welcome home lights all work ok so I should be ok for the MOT.

 

[St4n99]

. Is this normal? I would of thought only the little side lights should be on.

Is it possible you have changed something when testing with vsds ?, I have the h7 lights and when set to sides lights the dip beams are off but possibly different with leds . All your lights work so mot should not be problem

 

[Littleblackflash]

I'm using H7 headlights.
I didn't save any coding changes so it may of been like it for a while. Do you have a scan of your van to compare with, otherwise I'll check the VCDS settings later.

 

[St4n99]

Unfortunately I dont have vsds buddy , I just use carista for basic things with the van and fault codes ,it's when a read that you were using vcds to test the lights a thought it could be possible you have changed something without knowing , when just ignition on and light switch set to off I just have DRLs on , side light switched to on and it's DRLs and side lights , dipped lights switched to on and DRLs go off and just side and dips are on, I also don't have auto switch on mine so there may be a difference , hopefully someone will come along with h7s with auto switch and can confirm

 

[mmi]

The VCDS logs all coding and adaptation changes in folder C:\Ross-Tech\VCDS\Debug so just locating first line for the module will reveal the original coding.