Strange THQ LED headlight issue

[burnsy79]

The Mrs was very generous and bought me a set of THQ V1's with the LED bulbs all round for my Christmas. I eventually had them fitted in January and love them, all working as they should. A week and a bit ago I noticed that the full beam on the passenger side headlight was flickering on and off, even when the lights were set to '0' on my T6.1 Startline, and then that bulb stayed on. I've had an error to check passenger side full beam. If I unplug and plug back in the error clears, as soon as I flash the lights it comes back

I've swapped the LED's around and the same issue remains in the same main beam. To make it worse, the guys at THQ sent me another light cluster (thanks so much for your help THQ) thinking it may have been the unit, I tried the new unit that had halogens and that worked fine, as soon as I put the LED bulb in to the new unit same issue.

Not wanting to blind people all day with one full beam constantly on, I've swapped the LED's on main beam to halogen again for both and it works fine.

Has anyone ever heard of this at all?? The only change I've made recently is to have a towbar fitted with electrics... could this have screwed it up?

 

[The Flying Scotsman]

Long shot but check the fuses in your dash. I had bizarre things happening on my vans THQ lights and it turned out to be a blown interior light fuse.
No idea why that affected the main and rear lights but that’s what it was.
Worth a look

 

[burnsy79]

I’m still having this issue, you don’t know a good auto electrician in Scotland do you? Looks like it may have been caused by budget tow bar electrics…

 

[The Flying Scotsman]

I’m still having this issue, you don’t know a good auto electrician in Scotland do you? Looks like it may have been caused by budget tow bar electrics…

Good one along the road from me in Dundee.
He was in my class at the school and has a good set up.

 

[Fishinbrine]

Evening all, vehicle specific towbar wiring kits that use CAN modules cannot interfere with the lighting circuits in any way, the module reads specific CAN id's and outputs them to the trailer socket when the additional load is detected (through a trailer etc being connected) If your vehicle has been wired up using 'bypass' or 'universal' electrics then unfortunately this issue is entirely possible.

On the T6.1 many vehicle specific wiring kits also connect an analog brake light signal at the BCM, we don't advise this is connected on the T6 as it caused issues with incorrect bulb failure issues, however the T6.1 did not share this issue at all. (Ps, I design and develop vehicle specific towbar wiring for the UK market)
I would honestly suggest disconnecting your trailer wiring to see if you still have the flickering issue. If it goes, reconnect the CAN for the trailer module, retest, if ok, reconnect the analog brake signal, if the flickering re-appears, potentially leave this disconnected, brake lights on the trailer will still function over CAN.
If the problem remains with the trailer wiring disconnected then it's most likely your issue is elsewhere mate.

If you have no vehicle specific wiring for your towbar, I would seriously advise this to be removed and fit vehicle specific electrics for your towbar.

If I can help further let me know I'm more than happy to advise what I can for you

 

[burnsy79]

Cheers for the good advice @Fishinbrine, now I just have to figure out how to disconnect the tow bar wiring that the company did

Might leave that to experts… it’s in at an auto electrician next Thursday

Good one along the road from me in Dundee.
He was in my class at the school and has a good set up.

I’d love to do that, Dundee is just a wee bit of a trek for me though. Found a local auto electrician, hopefully he can fix and doesn’t rip me off too much.

 

[burnsy79]

So, I’m now 9 months in and circa £900 and this error is still about.

I had a local auto electrician look at it and he created a bypass by linking the driver light feed to the passenger, using a relay to even up the flash timing etc. after a few months of the contact errors I gave the van to a recommended VW specialist, they rewired the van back to OEM. For a few days it seemed to cure it completely but now it’s back with a vengeance. Full beam now on permanently…

I’m so frustrated with this van it’s aging me rapidly

Back in to VW specialist in Jan to look again. Every diag hour that passes is more cash spent.

Googled the life out this and it’s unique to me and my van.

 

[burnsy79]

Not sure if anyone is following this, but I FINALLY have proper working lights.

Turns out the issue was a dodgy wiring loom in the end. Looks like it had been snapped / cut / damaged at some point and someone had soldered them all back together. This likely happened when the van was still a commercial and the person did this to save them from buying a new loom. So a £170 loom has cost me more than £2k. Lesson learned and I can love my van again… once the pain of this fades that is.

 

[Sackmycook]

Onwards, upwards