Rear courtesy lights on with ignition - fade out as courtesy lights come ont

[kb-27]

Hi,

I've a T6 shuttle camper conversion, with the Skyline conversion roof where the mid light and ventialtion bar is moved to the rear.

I've noticed recently that the courtesy lights on the rear are now on when the ignition is on, but fade out as the front courtesy lights fade in once the ignition is turned off (and key removed).

I checked the rear re-wiring this evening, and it all seems ok. The behaviour is affecting both sides of the rear light bar (they are wired independently).

Is this likely to be a BCU reset type issue or a short somewhere north of the B pillar?

Any advice welcome

Thanks
Kevin

 

[manfrotto]

Not just a setting in the Infotainment system?

 

[Deaky]

It’s quite possibly a short to ground on the courtesy circuit, how quickly do the courtesy lights go off after removing the key?

 

[kb-27]

Hmm - thanks, the sequence below:

Unlocking
- Rear quickly fades on
- Almost immediately fades out as the front courtesy light comes on

Ignition on (with doors closed otherwise the front stays on)
- Rear fades on as front fades off
- Stays on until

Ignition off and key removed
- Rear fades off as front fades on as key is removed

Lock
- Read fades on as Front fades off, then almost immediately switches off with no fade

As mentioned above it's both lights on the bar which are fed off separate wires, so if it is a short I'm going to need to investigate the wiring in front of the B pillar, which I'm less confident on poking at, so any pointers / advice much appreciated!

 

[manfrotto]

That certainly sounds very strange like the BCM is confused, and therefore worth resetting the BCM to see if that fixes it.

 

[kb-27]

Ok, so a day tinkering with the light bar and a few other things.

I did the reset:
- disconnect battery both terminals for 1 hr
- short the leads before reconnecting

I've still got the same issue, interestingly, when I think the lights are supposed to be on I get 0.5v down the line, but this obivously then peaks when they actually come on as described above.

I can't see if either the BCM didn't reset, or whether as Deaky says we've got a short somewhere.

Still confused - will sleep on it.

 

[kb-27]

Ok, fixed it - details below in case anyone is paying attention...

Turns out @Deaky was right . I did the following:

• Dropped roof panel on that side
• Dropped out wiring loom and split out the Brown / Brown-Red / Red-Black wires
• At this point it stopped giving out any light at all - more on that later...
• Split the circuit where the join was from the single feeds from the front of the van to the mid, rear and tailgate lights
• Checked the rear end was working with 12v direct to it - all ok
• Removed the mid wiring which was bundled up (left 2 Brown feeds heatshrinked off but still in the loom)
• Extended the feed from the front and wires to the rear to the c-pillar where the camper conversion light switches are - I was intending on putting a DPDT switch in to allow them to be run on the domestic battery if I couldn't fix the fault
• Took the kids to gymnastics and cut the hedge
• Suddenly realised why the lights had stopped completely
• Replaced the fuse and it all sprang into life working as it should

I'm hoping that the short was on the section of wiring I've removed and replaced, I did check it, but time will tell. Even if it fails again, I now know where the issue is likely to be.

Thanks for the advice all!

 

[CooseVW]

• Took the kids to gymnastics and cut the hedge

This got me