Daimler V8-250’s just come back from having a new headlining and having the steering looked at, which meant removal of the steering column, by 2 different firms and now I’ve got no interior lights.
My meter shows 12V on both terminals inside te lights so it’s the path to earth that’s the problem.
I’ve looked at the only wiring diagram I’ve got (for a Jaguar) and all the lights have separate earths, which won’t explain why they all don’t work - I would expect a failed common earth to be the problem.
Does anyone know the actual routing of the earth wires? And are they commoned?
And in case it makes a difference - which I can’t see how - the instrument lights never worked.
Long time ago I did my lights but I think
You have live and earth going to lights , and they earth out on the door switches , so check they have connected all wires back on the light units , the earth stops at each door switch !
I’d start at one of the door switches and work my way back on the ground circuit to find the cause, probably a separated bullet connector under the dash.
IIRC, the door switches only have a single connector, as in the earth is fed via the body earth connection, not a separate wire. Interior lights and the clock are fed from the same wire and the same fuse as indicators and other things. If those are still working, perhaps the connector between clock and interior lights has become disconnected. They are daisy-chained, so if all are not working, the clock connection is the start point.
Thanks everybody - I’m making progress and the driver’s side is as good as done.
A PO had replaced the purple/white wire to the switches with a black one routed under the sill carpet and had used the wrong connectors so it had dropped out of a bullet connector under the dash. But curiously, half way down the wire there was a wrapping of insulation tape and when I removed it the wire had corroded internally & externally and gone open circuit where the tape was. Very odd and seems to indicate that I had 2 faults on this side and the lights didn’t work from the driver’s door from the time I got the car just under 2 years ago. It’s possible as I think I’ve only used it at night once.
The correct wire is on order and I’m going to try to route it through the sill as it looks quite easy.
A little footnote - rather a strange way to wire the lights? If it were me I’d run the power to the switches first then on to the lights and to earth local to the lights. Much less wire and connectors and the circuit is only live when the doors are open, rather than all the time.
Many years ago I scrounged a few old warranty MGB wiring harnesses which gives me a supply of all the color coded wires (and bullet connectors) to be used for repairs. Maybe the next owner will thank me for maintaining the color coding.
I found on my '64 Mk X the interior lights and the bright headlights are related to each other. I would suggest checking the wiring of the flick switch/turn signal lever on the column–maybe it got messed up when you were working on the column and the wires aren’t connected right now. At one point when my foot dipper switch failed I hardwired the brights on only to find that the interior lights then only came on when I flicked the brights position from the turn signal lever. Don’t recall why it did that but when I studied my wiring diagram it made some sense…
About 32 (Fahrenheit) here yesterday - borderline for me in the strong bitter easterly winds we’ve been having. But a bit milder today, with rain, so a good day for some work on the lights inside the garage.
Previous owners have added a number of wires of various incorrect colours over the years and I think it might take a lot of sorting out, and the fact that the colours on the fabric covered originals are not recognisable doesn’t help.
I had a quick look at the headlights the other day and it looks to me like a PO has fitted halogen bulbs - so the mystery of why my headlights are acceptable seems to have been solved.