The instrument cluster has the alternator warning light which also serves to tell the voltage regulator to turn on. Without the cluster, there is no signal to turn the voltage regulator on and no charge from the alternator..
There is a temporary fix, you need a 5 amp inline fuse, about 3 feet of 18 gauge wire and 2 each 3 way wire splices. DO NOT in any circumstance omit the 5 amp inline fuse, DO Not use a larger fuse!!!
Tap into the red/green wire on the coolant level sensor. That is 12 volts only when the ignition is on. The 5 amp fuse needs to be the first thing that connects to red/green wire. Connect the other end of the fused wire into the alternator harness green/red wire on the D shaped connector on the alternator. That will supply the 12 volts signal to turn on the voltage regulator only with the ignition switch is in the Run position.
If You choose a non switched source, for the 12 volts, you will definitely run down the battery..
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