Hey folks,

I'm running a 67 Ford drivetrain in my 55F100. I have an externally regulated 12 volt alternator. The wiring on this truck was completely butchered when I bought it and I've managed to gradually piece it together to get the truck running, lights, etc, but it is not charging.

The "S" and "F" wires from the regualtor all run to the corresponding "S" and "F" posts on the alternator. The "A" terminal at the regulaor splits- one part goes to the "Batt" post on the alternator and the other goes to the 12 volt constant side of the started relay. The "I" terminal is not hooked up. There is a yellow wire with a black stripe that runs near there and then goes into the cab where it is connected to nothing. I have bypassed all of the hacked up original ignition switch wiring and just added wires to get the basics to work.

If I jumper 12 volts to the "I" post on the relay or on the ignition resistor everything works perfectly but the truck will NOT shut off with the key any longer. I have to pull the wire off to get the truck to shut off.

If I jumper the "I" terminal straight to the "Acc" post the key will shut off the truck but while it is running the voltage continues to climb and climb...it reached 15.5 volts before I shut it off.

Anybody have any thoughts????

Also why does there seem to be a wire running to the steering gear box? Am I seeing something wrong here?

Thanks much,
Jay

 

Jay,

On the 'A' terminal, the split wire should be looped to the 'S' terminal of the regulator and then run to the ignition side of the switch. From there it goes through the ballast resistor and then to the "I" terminal on the starter relay. Look in my gallery for a wiring diagram for this system. The steering box wire is for the horn.

Vern

 

Thanks for the info. but what if I'm not running an ammeter? Can I just go straight from the Batt post on the alt. to the starter relay?

Also that makes perfect sense about the horn- I don't know how I didn't think of that.

Thanks, Jay

 

What is the current engine set up? Do you have most of the stock switches, gauges in place? If you have everything in stock form, except for the alternator, I would but the one wire conversion from Sacremento Vintage. I think it's about $30-$35, and would simplify your situation. It would be very easily adapted into the stock wiring system on one of these old trucks. These are some of the easiest rigs to build a wiring harness, and if you make your custom add ons simple, they swap right in with out any hassle. I put my 53 F-800 body on a newer frame with a CAT diesel, and the difference is an alternator, and a fuel shut off solenoid instead of a generator, and a coil. Quick easy conversion. 1 wire adapter for the alternator, and use the stock coil wire for the fuel shut off solenoid. This route will keep my wiring as close to stock and simple as possible. I would recommend the same for ease of installation, and to eliminate a lot of head aches.

 

Yes!

Vern

 

Thanks to everyone for all of the information. That diagram is exactly what I've been looking for for sometime.

The engine is a '67 390. All of the stock gauges are there but nothing is hooked up- instead there is a really cheap set of aftermarket gauges- of which the ammeter is NOT hooked up.

I will have to check out Sacramento Vintage- that is an interesting idea.

Either way I just bought 3 spools of wire and I will see what I can do on Sunday- thanks for all of the help!

Jay

 

Glad to help. That wiring diagram helped me through the wiring of a 65 Mustang I restored a few years ago. I like it because it is not so technical as a wiring schematic and anyone can follow it. Good luck with your truck.

Vern

 

Jay,
I have a 58. My wiring was butchered also so I pulled the entire harness from a 69. I was using all '70 guages including the ammeter guage. The '69 idiot light was not being used so I clipped the wire so that the light would not come on. In doing so I altered the charging system and when I finally spliced that wire back together my ammeter suddenly started working and my alternator started charging.. I don't know if this makes any sense or if it's even any help but good luck with it. John

 

John,

I went though something similar with my Mustang. That idiot light is the "exciter" in that system which tells the alternator to start charging. Without it the system won't charge. If you don't run an idiot light you can connect that wire to just about anything which will draw a small current when the switch is on and it will work, but you can't just clip that wire and leave it unattached or the alternator won't charge...

Vern

 

Thanks to evryone- I set up the truck today like the wiring diagram and everything is working perfectly. On to bigger and better things....

Thanks again-you guys are the best,
Jay