Join Date: Feb 2000
Location: Temple City, Ca
Pin 1 is the field and requires an excitation voltage to the alternator. If an alternator is new or has sat for a period of time it won't start without the excitation voltage from the key switch. The idiot light was added in there as a "extra feature" and is not the reason for the wire.
Pin 2 is the remote sense line. It's the line that controls what the alternator puts out. If everything is close together, tying it to the back of the alternator works. If things are spread out, moving it away from the alternator and closer to the heavy loads works better. The sense line then measures that remote point and raises the voltage slightly out of the alternator.
Unless I misread things you have 2 points that draw a heavy load while normally there is only 1 point. The 2 points are
1, The original fuse block
2, The new firewall connector.
Moving the remote sense wire, from Pin 2, to the firewall connector should help. As the big power items come on, the remote sense wire will see the voltage drop on the firewall connector. The alternator B+ voltage will then go up to compensate for the heavy load. In other words, we don't care about the voltage on alternator B+. We only care about the voltage on the firewall connector.
That should take care of the problem with the firewall connector. Since you have a very large wire from the firewall connector to the battery, the voltage should almost be identical. This should keep the battery charged.
The next problem that may occur is the voltage to the old fuse block. I believe you still have this tied to the horn relay. After you have the system controlling the firewall connector, this point needs to be measured. If this point is too low, the wire to the fuse block, in the harness, should be moved to the firewall connector. However, one thing at a time.
Yo-ho Yo-ho a pirate's life for me.