Instruments
 

On my 1981 SC, I have been having a problem with the oil pressure gauge needle just jumping around all over the place. I didn't think it was actually an oil pressure problem as the engine would have seized (!) but distracting anyway.
I lifted out the gauge from the dash and found a loose red/black wire another end of which led to the oil pressure light so guessed it was related & I re-attached it to a spare terminal on the gauge. It appears to work.
However, there was also a loose green wire behind there. Anybody know where that should go?
Cheers
David

David,

I don't have the wiring diagram handy but loose wires in the dash makes me cringe. For some strange reason Porsche did not design the instrument wiring to be on a fused circuit so you have a hazard on your hands. I'd suggest checking for any other surprises with your instrument wiring and look at adding a simple in-line fuse. The fuse is super easy. I'll look for the wiring diagram and the thread that shows how to install the fuse.

Here is a thread that shows the in-line fuse:

http://forums.pelicanparts.com/porsche-911-technical-forum/700218-fire-under-dash.html

Here is a link to the electrical diagrams. 78 should be the same for your 81 I believe.

Pelican Parts - Porsche 911 Parts Listings & Diagrams

Good resource on European wiring:

http://www.thesamba.com/vw/archives/info/wiring/Understanding_Euro_Wiring_Diagrams_Motor_Magazine_ April_2003.pdf

Thanks, Tirwin, that's brilliant. Much better diagrams than in my workshop manual. I will work it out tomorrow.
Cheers, David

Bouncing needle probably means faulty oil pressure sender

Look at my old post, you will find useful informations and pictures

http://forums.pelicanparts.com/porsche-911-technical-forum/520645-wiring-all-gauges-911-sc.html

Thanks for those links. The oil pressure gauge now works fine, it was just a loose connection on the back of the gauge.
I have taped up the disconnected wire and will wait to see what doesn't work!

My '79 has a loose green wire as well. I believe that it was just an extra in the wiring loom.