1934 Ford Model 40 Electrical issues

[DLR]

Hoping for some guidance. In 2016 purchased a 1934 Ford Model 40 that had already been converted to 12 volts. Always started and ran well.
I become seriously ill and fought a rare disease for over 4 years. Thank God, I’m here and fully recovered.


After a long period of sitting, I tried to start it. It didn’t start, I smelled something burning, looked under to hood and saw that the yellow starter switch wire (the one that runs down to the starter switch at the base of the steering column) and the yellow and black wire to the generator were singed and blackened on about 1/3 of the wires length. The covering actually melted into a hardened, carbon like texture.

Dug in and found the generator had a flash burn on the back by one of the vent holes. I replaced it and all of the wiring that burned.

Today I still have not been able to get it running, Most of the harness has been replaced. I got underneath and tightened all the connections.

The battery is fully charged
The starter motor turns, however, only after I disconnect the yellow wire running to the starter switch. If I leave that yellow wire connected, the battery terminal sparks when I try to hook up the negative side of the battery. Almost seems to be a dead short.

The lights will not turn on when the battery is connected and the horn only lets out a low moan but does not sound.

Not sure what to do next in my search for an answer. Hope someone else has experienced this. Thank you

[Terry,OH]

Hard to tell what has been done to your car to convert it to 12 volt. For the 6V, original wiring the foot start switch has three wires on one side of the switch: The battery cable, a yellow wire to the horns and a second yellow wire to the Ammeter. It seems you have a problem with the electrical circuit that the yellow wire to the ammeter feeds. Suggest you take it off of the start switch and place an ohmmeter on it and remove wires in that circuit until the short circuit clears, Do this with the battery disconnected. You can find a wiring schematic diagram on Mac VanPelt web site.

[fordyford]

What generator regulator is on the car? Could have the cutout points stuck closed?

[DLR]

Thank you Terry. I'll try this and let you know.
I'm also not sure I have the correct resistor on? Do you know of a good source for 12v resistors for the earlier cars?


Ps. My car looks exactly like your avatar

[DLR]

It's a 12v generator I purchsed from Vintage Auto Model # below. I'm not sure where the regulator is on the car



Delco Alternator 2 wire connector plug - P10SI

[petehoovie]

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Originally Posted by DLR

It's a 12v generator I purchsed from Vintage Auto Model # below. I'm not sure where the regulator is on the car

Delco Alternator 2 wire connector plug - P10SI

https://vintageautogarage.com/delco-...onnector-plug/

[Flathead Fever]

You have a dead short if it melted the wires like that. A tiny little spark might be normal when you hook up a battery cable but nothing more. I would look at the regulator too. I had the points stick on a '66 Mini Cooper S and it burned the harness. Unless that is not a generator, but a alternator made to look like a generator, then it could have an internal regulator. I don't know why the yellow wire to the horns and the generator wire would burn. Look at the ammeter if it has one, it might have shorted out internally, especially if it wasn't rated for the alternator current. If all of the voltage runs through the ammeter nothing will work if it fails. Remove the wires and connect them together bypassing the ammeter. The wires to the ammeter could have also shorted or it could be one of a hundred other things. You need to disconnect stuff until that spark goes away, that will lead you to the cause.


This is the inexpensive tool for finding shorts. Looks like a piece of junk but they work great. Disconnect the battery which it should already be disconnected if you have a short. Hook the circuit breaker between the battery and the cable. That way it will pulse a current through the short without burning the wires, like a turn signal flasher. You slide the magnetic ammeter along all the harnesses until the needle starts swinging back and forth. That is the harness with the short. You continue to slide the meter along that harness until the meter stops swinging. When it stops you have gone past the spot where the short is. We had aerial boom trucks at the phone company with miles of aftermarket wiring that could rub on something and short out. This is how we quickly found those spots.

https://www.jbtools.com/sg-tool-aid-...RoCDZUQAvD_BwE

[DLR]

Thank you: This is the alternator which replaced the one that burned.


Alternator 12 volt neg ground 100 amps black- ABSI-100-SEL

[DLR]

I dug through my info It is an


Alternator 12 volt neg ground 100 amps black- ABSI-100-SEL



It replaced the alternator that burned up.