The recently replaced alternator on my kid's 86 244 decided to mostly stop working. I took voltage readings at various places and found no voltage at the field wire. I disconnected the field wire and got 11 volts with the car off and the switch in "run" As soon as I hook the wire up to the field terminal the voltage drops to almost nothing (1 volt). If I hook a jumper from the armature(big red wire) to the field connection, the alternator seems to work fine, boosting battery voltage from about 12.5 to about 13.5.

I took voltage (battery connected) and ground (battery disconnected) readings at various points with the following results
Armature 36 Ohms 12.5 volts
Field wire 12 Ohms 11 volts
Field connection 21 Ohms
Alternator case 0.5 Ohms

Later, I started the car and the alternator worked just fine. I shut down and restarted the car. The alternator did not work until I applied voltagr to the field terminal via a jumper from the armature terminal. After removing the jumper the alternator continued to function. I shut down and estarted the car and could not get the alternator to work using any of the previously successful methods. This is driving me crazy (short trip)

It seems that maybe my field wire is grounded and leaking to ground instead of flashing my field. I am considering running a temporary field wire to test this idea.

Does anyone know of a handy switched power source in the engine compartment that I could use? Any other ideas would also be appreciated.
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Blane Gardner Couple of Volvos, a Toyota Van, and a Couple of Old Chebbies