John Ha wrote:

The red wire and the yellow wire, taken separately, always have power applied to them - even with the key off.  Is that really what you want?

 
The yellow wire is not being used.  It has no power connected to it.  In the picture you see the yellow wire with the black wire.  The yellow is for the factory gauge, I’m not using factory’s instruments.   The black next to it would connected to the starter solenoid and would power the voltage regulator, which I’m not using because of the one wire alternator and the black wire will not be connected to anything so no power at the voltage regulator connection.

I need to review the wiring for the autometer gauges but I believe I need 12V from the battery and then another 12V from the key on position.

Thank you John.

BobE wrote:

RTM - I'm not sure if you it but I emailed you the 66 Mustang wiring diagram.  
Make sure you've got the correct yellow wire.  A yellow wire is used in several circuits. 

 
You did and I’ve checked this wire a million times and reviewed the drawings a million times.  I used my meter to confirm which wires are which.

True74yamaha wrote:

Yellow black goes to alt light and green/ red stripe is the alternator exciter wire. Dunno if you need an exciter wire for the alternator that you have. Just thought I'd throw this out there

 
The black/red and white in the alternator harness are not used.  I may use these extra wires to power the cool guy fan controller.   I’ll mount the controller were the voltage regulator would normally go.

I would not recommend using the pink wire for anything. I almost burned my car up using it for a 12 volt source. It is a time bomb. 

BobE wrote:

Mochaman wrote:

I would not recommend using the pink wire for anything. I almost burned my car up using it for a 12 volt source. It is a time bomb. 

I agree, find a 12v source.  The resistor wire will drop the voltage to like 9v. 
 

 
I’m not using the pink resistor wire for anything.  I’m bypassing it.