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rmartservices

1929 FORD MODEL A

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I HAVE A 29 MODEL A STRAIT 4 ALL ORIGINAL I HAVE A PROBLEM I CHANGE THE FAN BLADE BECAUSE HOUSING BROKE AND I PUT IT ALL BACK TOGETER AGAIN AND NOW WHEN I CONNECT THE TWO WIRES ON TOP OF ALTERNATOR ONE WIRE CONTROLS THE LIGHTS AND HORN AND THE OTHER WIRE GOES TO FIRE WALL WHERE COIL IS WITH JUST THE LIGHTS HOOK UP THE CAR TURN ON BUT AFTER A WHILE IT SHUTS OFF FOR NO REASON IT STARTS BACK UP AFTYER A FEW TIME BUT KEEPS HAPPENING WHEN I CONNECT THE OTHER WIRE TO IT THAT GOES TO THE FIRE WALL THE INSIDE METER MARK GOES TO NEGATIVE SIDE AND WHEN I REMOVE IT AGAIN IT GOES BACK UP TO CENTER AGAIN ANY IDEAS ANYONE NEED HELP RAY IN CT

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Do you actually have an aftermarket alternator or an original generator with the cutout mounted on top? If you have the type with the cutout, the contact of the cutout could be stuck which would cause a negative discharge at the ammeter. Sometimes, you can take the cover off the cutout and unstick them, or you might need a new cutout (I would buy the voltage regulator, modern type of cutout they make now).If you post some photos, we might be able to better diagnose it.

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Ray,

Attached is a wiring diagram of how the wires should be routed. The black/yellow striped wire from the generator(alternator) goes to the driver side post in the junction box. From there, a wire goes to the passenger side post of the ammeter. (sometimes though,the wires on the ammeter need to be swapped right to left. If it shows a +charge when you turn the headlights on for example, switch up the wires) A short black wire then goes from the drivers side post in the box up to driver side post on the coil. A red wire comes down from the ignition switch through junction box and is connected to the passenger side of the coil. The wire within the armored cable from the ignition switch goes to the distributer. The plain yellow wire brings the power from the starter switch to the left post on the junction box. From there it goes to the right post of the ammeter.

Are you saying that when you hook up the yellow wires for the lights and horn to the generator, but leave the yellow/black wire disconnected, it will start and run for a while? But when you hook up the yellow/black wire to the generator your are getting a large drain, as the ammeter is showing a discharge. If so, I guess theortically the car will run with the yellow/black wire not connected to the generator, but that means that you are running straight off the battery only, and the generator is not charging the battery back up.

This could be why the car dies out after runnig a while - the battery is being drawn down. But you said it will start back up, so that doesn't make sense. If when you hook up the yellow/black wire, you are getting an immediate discharge, I suspect there is a short in that wire somewhere. Check the insulation along that wire all the way through the loom that the wire passes through from one end to the other. I'd bet that the insulation is frayed somewhere, and it's shorting out.

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Your pics were very dark, so I enhanced the one of the junction box. From what I can see, let's say that you have some non-standard wiring going on there. Unfortunately, there's very little advice anyone can give on this forum because the wiring is so non-standard. You need someone there, live, to look at what you have and troubleshoot it.

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The best thing to do on your Model A-or any other car with old wiring-is to get a proper, complete wiring harness and rewire your car. Any wiring that is 30-40-50-60-70-80 years old is prone to failure at best and could burn up your car and/or your garage at worst. Also, make sure you install a battery cut off switch as well. A complete Model A wiring harness can be had for about 100.00 for any of the larger vendors like Snyder's in New Springfield, Ohio or Brattons.

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The best thing to do on your Model A-or any other car with old wiring-is to get a proper, complete wiring harness and rewire your car.

I agree - for under $200.00 you can replace every stitch in a model A or T - well worth the investment IMO.

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