Strange interior lights issue

[VW_Hutch]

Hello all,

I have a very strange issue that after scouring the Web for hours and trying all the advice can't seem to get to the bottom of.

So I have a works Van (Renault Trafic 72 Reg) which is a cracking van. OEM lighting for the cargo bay in the back is really poor so like I've always done with all my vans is buy LED 12V lights from Amazon. Put them in back in February and they've worked absolutely perfect all year making the read really bright to help me rattle about for tools on night shifts.

The other night they have stopped working...except they still work. So basically I can turn the dome switch to manual ON and the lights work but when in the middle position which is for the rear doors or sliding door opening to trigger them ON doesn't seem to work. It's really annoying and I've checked fuses and all sort and can't seem to find the problem.

I can't see it being both door switches going at rhe same time and it's really strange cause for months it's been fine. What really makes it confusing is they do work but not when the doors open I have to manually open them.
The lights are secured with double sided sticky tape and wired to the done light with a W5W wiring adaptor.

Cheers

[VW_Hutch]

To add I've checked the back of the light fittings and they have no corrosion or thermal damage either. No ends of my led lights are bare or shorting. Front lights work perfectly fine with front doors. I'm at my wits end it makes absolutely no sense

[mdb55]

Have you double checked the physical connections to the dome switch when in the middle position? It sounds like its the side/rear door not triggering the connection through end to end: agree it's unlikely to have both door switches go at the same time, so perhaps more likely at the light dome end.

If you had an OBD2 scanner/reader, some of them will tell you if the status of the various light switches, so in this case if opening the rear/side door is triggering an event in the first place. That in itself wont fix it, but it might help pinpoint where the break in connection is.

[VW_Hutch]

Yeh I've got a OBII scanner coming to check the van (I used to have one but lost it when I moved) and will check the dome switch connection with my multimeter make sure I've got 12V on both permanent and the switched supply

[VW_Hutch]

So done more digging today. All door switches are completely fine switching 12V when and where they should.

What appears to be the issue (will confirm tomorrow) is the wiring plug that plugs into the dome light. In it there is a Red-Black- White cables.
From what I've worked out with my meter is that red and black are rhe constant 12V with white being the switch wire from the door switches for when the dome light is in the middle position.

From the photo the white pin crimp and terminal look damaged in a way so plan is to connect my LED strip lights to the White and see if when the door opens they come on. If so I need to find (which has been extremely difficult so far) replacement plug and should work. 2nd terminal from left is white.

[mdb55]

Thanks for the update, that all sounds consistent with the problem and likely diagnosis. Good luck with the fix.

[VW_Hutch]

mdb55 said:

Thanks for the update, that all sounds consistent with the problem and likely diagnosis. Good luck with the fix.

I tried taking the white and putting it with the Red for the LED lights...no dice.

I did notice when the white and black touch the other light worked 🤔 I'm wondering if it's a switched earth so to speak being a DC system. I really need one of the 6 pin connectors but really struggling to find the one for a Renault Trafic. Next thing I'm trying will be red to red and black to black from the 6 pin to the LED lights