Calling Electrical Guru's - Possessed 69 912

[gregaz]

Friends,

Cross-posting this from 912 BBS, as it seems that my electrical issue are fairly unique, and not many are contributing over there.

TLR - went to fix my taillights, broke my entire car.
Current standing - ignition switch is sorted, car starts, runs and shuts off. Light switch is messed up - with lights on, the electrical fuel pump turn on (it gets it's hot lead from the ignition switch only). I am totally stumped - any and all help is appreciated!

Writeup and pics as of yesterday here (the rest in the history of the thread): 69 tail light MESS - where to start? - Page 3

Many thanks in advance!

[tomolmsted]

Since car didn't originally come with electrical fuel pump that could be the problem. Where is it getting its power from? Considered disconnecting it for now and go direct to battery with inline fuse, toggle switch in car, and make sure you have good ground on chassis. Good luck.

[gregaz]

Originally Posted by tomolmsted

Since car didn't originally come with electrical fuel pump that could be the problem. Where is it getting its power from? Considered disconnecting it for now and go direct to battery with inline fuse, toggle switch in car, and make sure you have good ground on chassis. Good luck.

The power comes from terminal 15 on the ignition switch (which is only activated in right and start position).

This is the mystery - why is it coming on when I turn the lights on?!

[tomolmsted]

Electricity will follow the path of least resistance to ground. That very well may be through the light circuit. Verify clean metal to metal ground where the fuel pump is grounded.

[tomolmsted]

Another option is to add a relay to power the fuel pump. So the ignition switch powers the coil in the relay allowing 12v to go directly to the fuel pump. Should be instructions online on wiring it up.

[donporfi]

There is a post on the 911 Pelican Forum regarding the headlight switch.
I do not know if the switch you are using is the same as the one pictured in that post.
Here are some pictures and contact numbers and what they do.
Sorry do not remember the post name.

[Fixer]

Don't run your FP off your ign switch.
Separate switch