When to give up on original electrical circuits...
 

Hi All,

I need your advice regarding making "modifications" to the electrical system. My car has interesting electronics at the best of times, the oil level guage goes to full when the lights are turned on, if the lights are put on at park, only one headlight lights, but when ignition on, both come on, etc., etc......

So my actual problem is that one of the rear licence plate lights is out, but it is not the bulb. I have traced the wires to behind the tail light and am getting no voltage at that point (all taillights are working... currently!).

So the question i am asking is why don't i just run a line from the working number plate light to the non working one? The other option is to further trace what looks like non-original wires through the car to the front, or to where i find voltage.

I think you can see which way i am leaning, but of course i value your opinions.

(I should add it is a US RHD convert 1977 911)

Regards,

Chris in Australia

rhd convert, do what you have to do, it's already chopped up. you can tap into the tail lights in the engine compartment and run a wire to the licence plate lights. that will work fine, have a fosters after!!

Hi Chris,

You could of course run power from the working one to the non-working one. First you should check your non-working one has a good ground. Check for continuity between the ground side of the bulb holder and the chassis frame. Bad grounds are a common source of problems.

It sounds like you have many potential issues. If you love your baby like I do you'd track down the problems before long. I had a very mild electrical fire that could have easily burned the car to the ground. In my case many POs had bodged wiring together leaving burned, naked instrument lighting wired in, stereo wire for the headlights and other rediculous stuff. The last straw was an unfused fuel pump power wire (there were 2?) grounding itself on the fuel pump itself. All the smoke escaped out of my wiring.

Not sure this is an option for you, but if you can get a copy of the factory workshop manual which has an excellent wiring diagram, with a basic multimeter, you can track down and properly repair virtually any wiring problem. I have had a lot of electrical problems with mine over the years and methodically hunted them down. They really are fairly simple once you decipher the wiring diagrams.

you have normal electrical issues like everyone else. you just need to trace the circuits. the license light has a separate fuse. headlights have 4 fuses, etc. nothing wierd for someone who understands auto electrics.

FYI Electrical diagrams here: Pelican Parts - Porsche 911 Parts Listings & Diagrams

Although not for your year, they should help.