12V on Both Sides of Connection

[luvndasun]

Hi,
Problem is with the 14-Pin Connector mated, the car wont turn off. To turn the car off, I can either disconnect the 14-Pin connector or I can remove the 30A fuse between the alternator and Pin13.

With the car not running, if I disconnect the 14-Pin Connector and measure the voltage on Pin13/Red Wire from alternator, I get 12V on the Male Pin, its always 12V/hot, even with the key in the Off position. On the female side at Pin13, I get 0V with the key off and 12V with the key On. Should the Male Pin13 always be hot? Is it a problem that there is 12V on the Female Pin13 when the key is turned On?

Thanks!

[Porboynz]

Pin 13 on my 72 feeds 12V from the ignition switch to the middle pin of the CDI. I do not see any alternator connection for pin 13 but pin 14 has a red wire from the alternator to the rear window demister relay via the 3 fuse mount on the engine relay panel. What fuse are you removing to shut the engine down? My understanding is that the CDI and fuel pump get unfused 12V from the ignition switch. Did this problem just suddenly happen or did you change something?

[T77911S]

i dont have much experience working on the electricals on the 911, but looking at the diagram i would look at the 3 fuses on the side of the relay panel in the engine bay.
perhaps someone rewired something there. check the wiring for non original splices.

i dont think pin 13 is to the alt either. with the connector removed, and pin 13 getting switched power, i would think the ignition switch side is working. i would be looking in the engine bay side for the problem.

[pete3799]

Could be a faulty ign. switch.

[luvndasun]

I put in an alternator with an internal regulator. I also got rid of the the three fuses in the engine compartment. The 30amp fuse is what I put in between the alternator (B+) and the 14pin connector. It sounds like the ignition side is working as it should. What is the path back to charge the battery for the alternator B+ wire?

[Porboynz]

The alternator charges the battery via the thick wire from the alternator direct to the main starter terminal, the charge path does not go via the relay panel. If you have removed the 3 fuse mount then you need to ensure you bypassed it correctly. Same as with the internal regulated alternator, sounds like you need to check both these mods because you are getting 12V to the CDI that bypasses the ignition switch once engine is started, must be that 30amp fuse incorrectly connected and backfeeding.

[T77911S]

basically what he said.

one of those fuses was tied to the B+ on the alt (red wire), i bet you connected that to the red wire to the CD unit. (according to the 73 diagram onpelican).

[E Sully]

Changing from an external regulator to an internal should have been mentioned in the first post. It changes a few connections.
Below is a diagram I did when I had a 1986 engine with an internal regulator in my 1973. Pin 14 would be the connection to what would have been fuse 3 on the rear panel. This is where your added fuse should be for power to the rear defroster relay. Power for the CD box is from ignition switch (non fused) side of fuse 8 in the front trunk.
Pins 12, 13 would no longer be used since it was for the external regulator.
I can't give you the exact answer since mine is a 1973 cis and there are a few small differences, plus I don't know exactly how you rewired eliminating the fuse block.

[luvndasun]

Ok, thanks now it makes sense....The alternator charges the battery via the thick wire from the alternator direct to the main starter terminal. For my set up with the three fuse panel removed, I only need the Alternator B+ to go to the #30 lug on the starter.
Thanks!