[ebry710]

Originally Posted by VetteVet

Well your statement that the charging light doesn't work and the fact that it's a three gauge panel helps a bunch. The alternator needs to see some resistance to charge the fields and to prevent the diode trio from burning out.
hopefully that hasn't already happened. It also needs the resistance to prevent feedback from the alternator circuit to the key switch ignition wire which would allow the engine to keep running when the key was turned off.

The bulb provides this resistance as well as a resistor wire from the key switch to the inside of the firewall block where it becomes the brown wire to the external voltage regulator. The three diagrams below will illustrate this.

This one shows the resistance wire and the bulb with the resistance wire as a back-up in case the bulb blows and the resistance wire also is needed for the seven gauge panel that has no charging light.

Attachment 785738
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Do this mean that the gen light doesn't go to ground, it just is place in the circuit between the ignition switch and the fourth leg of the regulator.