No License plate lights (1973 911) .....

[Haasman]

Discovered no rear license plate lights while getting ready to head to RRVI.

-checked
· bulbs, they are good
· the fuse in trunk, good
· No power to the connector ahead of the fuel filter area in the left engine compartment.
· re-seated the ground behind the above

Not sure where to look at this point.

Does the license plate light pickup power off of the left-rear tail light assembly wiring loom?

[HarryD]

Per my wiring diagram, a grey wire goes from Fuse #7 in the lower box directly to the light. It appears to be bundled with the wires to the left light housing. I have the same issue and am unable to locate the power.

[Haasman]

Harry- Did you ever solve the mystery?

[HarryD]

Harry- Did you ever solve the mystery?

No not yet.

Have not had the energy or desire to chase this down. Probably a good COVID project for an afternoon of hiding from the wifely unit.

[ejboyd5]

Power for the license plate lights goes through the main headlight switch so you have a fair amount of wiring to trace. If you are interested in finding the fault, attach a tone generator to the gray wire at the plate light and work your way back up the food chain. If you simply want the plate lights to work, take some power off a tail light.

[Haasman]

Thanks ejboyd5 .... just was thinking about tracing with a tone generator. Ideally like to find the fault and keep it as stock as possible. But good point, grabbing power off a tail light wiring would be easy.

[Arne]

The reason the license lights come straight off the headlight switch is so that the license lights are not tied to either side of the tail lights. That way they do not illuminate with either of the single-side parking lights (turn signal with ignition off).

Probably not a big issue for us in the USA, but that's the rationale, anyway.

[LiveFromNY]

If you have a spare headlight switch, might be worth swapping it out as a quick test. I had the same problem years ago and never resolved it. When I had to swap out my headlight switch for other reasons, my license plate lights magically came back.

[edmayo]

All you need is a 12v. test light. go to the fuse block #7 lower fuse block. Turn on park lights, do you have power to both sides of the fuse? if yes, go to rear of car, if not then you're not getting power from headlight switch. If yes go to rear of car, follow wire harness from license lights to to connector just below fuel filter, unplug it, are you getting power from forward end of connector, if not there is a break between fuse and that connector (not likely, but possible) if power from forward end of connector then power is lost between there and the lights. Go to lights, remove one and test for power at grey wire spade. It will be something simple,,,,once you find it.

[Haasman]

Thank you Ed. As always your advice and instructions are clear and directly to the point.

Will report back.