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so, i have a 79 engine and trans in a 72 truck. things dont work quite right. I have most things working well enough to drive, but my battery doesnt charge. How would I go about hard wiring the alternator (turning it into a generator)?

Thanks,
jwalk0n

My 77 has a white with green stripe and white with black stripe running to the field terminals from the voltage regulator. It has a heavy black wire running to the battery. When the voltage regulator applies power to the field, it generates AC which is rectified by internal diodes and then the DC flows to the battery. To get power, you have to have power from the VR to the field, working diodes, and the black wire to the battery.

Have one of the DIY oriented auto stores check the alternator if you seem to have the connections I mentioned.

Ditto, most all autozone and those stores can check them. A NAPA stored checked my sisters astro van one.

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75 Luv, 350 V8, TH350, Camaro rearend. New 1975 Luv Step side. Stock for now.
Grandmaster of the "Shade Tree" way.. I can't see the yard for all the cars. Come on down and we will sit on the porch and watch the grass grow.

The problem with hard wiring is you still need a voltage regulator, unless your alt has a internal one.

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Certified pilots, looking down on people since 1903.

@Labman, PapaG: I'm not sure you read my post, if you did, I must not be understanding your solution.

@Luvrv8: What about an inline voltage regulator of some kind? (the 79 voltage regulator does not play well with the 72 truck and the 72 voltage regulator does not play well with the 79 alternator)

OK, I didn't realize the 72 and 79 wiring were different. Suggesting having the alternator checked was based on the idea it was hooked up correctly, but not charging.

I checked and my regulator has no less than 6 wires running to it. 2 go to the alternator, one to the battery, and maybe one to the fuel pump relay. I find the wiring diagrams I have very hard to read. You may need to find and figure out both a 72 and a 79. If you have the 79 regulator, you may only need to connect the ignition to the batt terminal on it and the field terminal to the alternator field.

I think the big change in wiring was between 76 and 77. The one wire to my alternator may activate the field, and the other supplies power to the fuel pump relay and idiot light. So if your alternator has 2 wires from the regulator, you only need to identify those 2 on the 72 regulator and connect them.

Look things over and get back to me. I may take more time tomorow to give more details.