All interior lights (courtesy and reading) not working

[mik82]

Hi
I've searched a bit on here, but can't find anything that fits
I have a 2012 (old shape) connect. I think there may be a few differences in the electricals as the fuse numbers don't match with the Haynes manual.
I fitted a rear interior load light, taking a feed from the central load light.
I didn't notice that I'd reversed the terminal connections on the new light - it was all working fine with the lights removed from their locating slots and hanging free.
Pushed fittings back into place. Lights came on when opened door as expected, but wouldn't turn off. I tried to find out what was going on, there was a relay click and they went off again

Now all of the interior lights don't work at all. I assumed as the positive feed was likely shorted to ground it was the fuse, but it's fine. The relay seems to click off/on when opening doors, turning the ignition etc.

Any ideas?
Thanks

[Kenton]

They can sometimes short out on the bodywork behind the light fitting when installing.

[mik82]

Yeah, I guessed that was what had happened - The light fitting is the standard connect dome light, so very easy for the frame to touch the bodywork, if the positive feed is connected to it.
The issue is now no interior lighting working, but with a fuse that hasn't blown
I took the interior light relay out and tested it - seems to be working fine although it was warm when I removed it - possibly as I'd had the doors open?
I'm not sure what else to check. The Haynes manual has a battery saver relay - but I think this relates to the older connect.

[Kenton]

May sound stupid, but have you double checked the bulbs are ok using a separate power source? Relay warming up is normal, but if it gets too hot, it sounds as if maybe there is a short existing somewhere still? Try removing the relay and giving it a light but proper couple of taps against a hard surface, then replacing and trying again.

[mik82]

Thanks. Yes, have gone through the bulbs and all working fine.
I think the relay is working correctly. From what I've worked out, the courtesy light relay is actually switching the negative side of the lighting circuit.
Looking at it, I think the initial problem that occurred - with me unable to turn the courtesy and dome lights off at all is because I was bypassing the switched part of the circuit - touching the negative feed to the lights to the earth via the chassis, rather than the short that i originally thought
Using a multimeter there's continuity between the negative feed to the lights, and earth when the door is opened, and i can hear the relay click. After a bit of time with the door opened, the relay clicks off and the circuit is broken
The fault seems to be in the positive limb of the circuit - everything would point to the fuse but this is working fine.
Annoyingly the Haynes manual wiring diagram seems to be for an earlier model! There must be something I'm missing.
From what I can see, the newer models have a "GEM" module that has some control over the lighting - so is it worth me connecting an OBD reader?

[rodders1959]

Hi. I have a 04 diesel lwb with the same issue. The Haynes wiring diagram is wrong. The power to the relay coil is there, but none to either side of the relay switch. Can anyone advise where I may obtain a correct wiring diagram or offer a solution to this problem. Where does the power come from that's meant to go to the switch part of the relay?

Tia.

Rodders

[mik82]

I'm not sure whether this helps you or not, but I solved this problem

I noticed my horn wasn't working, replaced the horn fuse and the interior lights started working. Obviously the lights run off a spur from the horn circuit.

[APH]

Hi. I have a 04 diesel lwb with the same issue. The Haynes wiring diagram is wrong. The power to the relay coil is there, but none to either side of the relay switch. Can anyone advise where I may obtain a correct wiring diagram or offer a solution to this problem. Where does the power come from that's meant to go to the switch part of the relay?

Tia.

Rodders

The relay switches ground to the lights, not power, you will not see 12v at the relay, other than the coil.