Hi everyone, I am working on a ‘56 Ford F100 that a previous owner converted to 12 volt, but did not use a wiring harness so wiring has been a mess. The truck was running well (272 V8 Y-block). I am installing a refurbished generator after the previous one died. After install and wiring exactly as the previous one was wired, as soon as I reconnect the battery (before I can polarize the new generator) the ARM wire gets incredibly hot and the battery immediately begins losing its charge. Any ideas what is connected wrong that I should change? Thanks for any ideas.

 

1956 F100 came from the factory with 12V systems. Negative ground. Find a 1956 whirring diagram or shop manual to verify it is wired correctly. Ifyou do not get any more help in a few days I will copy my shop manual wiring diagram.

 

Assuming you are connected correctly between your voltage regulator and your generator, you know A to A, F to F, a ground wire connecting the voltage regulator and the generator together. If all that checks out, It sounds like you have a bad voltage regulator.
Inside the voltage regulator there is a set of contacts (a cut out relay) that disconnects the battery from the generator when the vehicle is not running. If it wasn't there or its contacts melted together, the battery would discharge through the low resistance windings of the generator when the engine is not running. To test it I would use a test light or voltmeter. Disconnect all the generator wires from the voltage regulator. Keep the B or Battery wire connected though. With the battery cable positive reconnected test your test light by temporarily touching the B terminal of your voltage regulator. It should light. If it does next touch your test light to your A terminal on the voltage regulator. It should NOT light. If it does, your have a bad voltage regulator. So replace it, but before you reconnect the wires, the Ford Service Manual says to polarize your generator by momentarily touching the battery wire and field wires together with the engine not running. You should see a little spark. At that point, your generator should be polarized. Now you might want to temporarily disconnect your battery and wire your new voltage regulator back up. Reconnect the battery and you should be back in buisness. There is always a chance though a previous owner may have used a different style of generator and voltage regulator that uses a Armature powered field. If that happens, we will have to chat more!
I hope this helps!

 

Thanks everyone - it was the voltage regulator. I was able to replace it this last weekend and I can see output now coming back to the battery. Thanks everyone for your help.

 

Glad to hear you fixed it Seth!