[RESOLVED] Interior lights BCM ground not working after LED change

[The_Lad]

Hi All,

My interior lights have been wired up and working for a few years, the cab lights are unchanged but the rear lights have been rewired to take +12v from the leisure battery and a ground from either the leisure battery or the BCM ground when set to come on with the doors opening. This has all been working fine however yesterday i swapped the bulbs i have been using for LED ones from travelin lite.

Cab bulbs x 3
Kombi step light
2 x roof lights

Now when i unlock the van the lights dont come on same when i open the door

my best guess is something to do with the LED lights not drawing enough current so the BCM not detecting something? if i switch them to on using perm ground all works fine

Any ideas before i start swapping normal bulbs back in?

Cheers
Justin

 

[Dellmassive]

got any pics of tghe old/new lights,

and also the +12v feed and the NEG switching . . .

have a look over here:

LED Interior Cargo Lights - How I Done It.

LED rear interior lights - How i done it. so a few have asked, so i though i would just list it here as a post so i could refer back to it in the future. The lights were purchased from The T6F shop over here > We were planning to do the carpeting at around the same time, but for the purpose...

www.t6forum.com

also check for possible blown interior light circuit . . .

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also look at a BCM reset incase its locked out the circuit for some reason:

[Guide] Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

Full Van ECU Reset (Capacitive Discharge) -- How I Done It -- The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right. The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system...

www.t6forum.com

..



keep us posted, and post some pics . =]

 

[The_Lad]

The old lights are just the bulbs supplied by VW ie the filament ones, the new ones are just bulb replacements from Travelin Lite the physical light housings havent changed at all

ill try to get some pics over the weekend when im home, and ill see if swapping old bulbs back in one at a time if it starts working again

 

[Dellmassive]

have you tried reversing the buls polarity in the socket?

have you used a meeter yet to test for voltages and grounds?

 

[The_Lad]

I haven’t done any troubleshooting as yet, the bulbs only work one way round as I recall but will check I can’t see it being a wiring fault more related to the bulbs at a guess as nothing has changed and it’s been working for years

 

[Deaky]

Possibly shorted something while changing the bulbs and the bcm needs resetting?

 

[The_Lad]

Ill try the BCM reset before changing bulbs again and see if that sorts it

 

[The_Lad]

Ok just to close this off as it could be useful for someone.

I performed a BCM reset and it all worked until I put the ignition on and off then it all stopped working again. I noticed that using the switch and buttons in the cab for map lights and on/off/door were giving wierd results.

anyway the issue was the center cab bulb was working with the bulb inserted in both directions but only working properly one way round, when in the wrong way round it worked but caused the wierd issues with the switches and other lights.

Put it the right way and all ok

 

[Markie-Boy74]

Hi All,

My interior lights have been wired up and working for a few years, the cab lights are unchanged but the rear lights have been rewired to take +12v from the leisure battery and a ground from either the leisure battery or the BCM ground when set to come on with the doors opening. This has all been working fine however yesterday i swapped the bulbs i have been using for LED ones from travelin lite.

Cab bulbs x 3
Kombi step light
2 x roof lights

Now when i unlock the van the lights dont come on same when i open the door

my best guess is something to do with the LED lights not drawing enough current so the BCM not detecting something? if i switch them to on using perm ground all works fine

Any ideas before i start swapping normal bulbs back in?

Cheers
Justin

Hi there. I have the same problem. Tried everything the same as you apart from the BCM reset. How do you the BCM reset as I’ve never done that before? Cheers Mark

 

[Dellmassive]

BCM RESET HERE --->

[Guide] Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

Full Van ECU Reset (Capacitive Discharge) -- How I Done It -- The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right. The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system...

www.t6forum.com

.

 

[Markie-Boy74]

BCM RESET HERE --->

[Guide] Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

Full Van ECU Reset (Capacitive Discharge) -- How I Done It -- The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right. The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system...

www.t6forum.com

.

 

[Markie-Boy74]

Thank you. Has anyone tried this. Does it work? I would hate to have something else go wrong by doing this as it’s my work van. Cheers

 

[sparkzer]

Thank you. Has anyone tried this. Does it work? I would hate to have something else go wrong by doing this as it’s my work van. Cheers

If it didn't work, @Dellmassive wouldn't have posted it and written a guide about it!

Seriously though, this is a pretty standard thing to do on modern vehicles and electronics in general.

Good luck!

 

[Dellmassive]

Yes... It's the equivalent of "switch it of and back on again"

Just the windows and radio time to reset after.