OK, I've got a Ford 100 amp 1 wire alt to install on my '72 F-100. 390 and 4 wheel drive. I've seen 17 different ways to do this on this site, does anybody have any knowledge on how to do it right? Half of the peeps say "just hook up the wire to the battery". So I did that and ended up with a completely dead truck. I know 12 volts has to get to the fuse box and wherever else.

 

if you have just a one wire alt that has been converted to that...it jsut hooks to the solenoid that the batt hooks to. If the truck sits over a week it will run the batt dead, that is what the alt shop told me when i was asking info about converting to it, it is constantly sending ower to the field side IIRC

 

I have never heard that before(running down the battery). Sounds like he didn't want you to buy one.

You are right about the starter relay connection though. Look at point number 3 in the diagram below. You should have a smaller wire connected there. This wire runs the whole truck. If you miss it, you will be dead in the water. And this is where you hook the one-wire alt.

 

Thanks for the pic. Whatever wire (if any) that was hooked to that #3 post I left on. Still nothing. The other day my truck went completely dead (everything) while going down the road. Eventually I found a wire in the reg harness that went to the harness that was headed for the fire wall. this was a fusible link that went bad. so I'm thinking just hook 12 volts to that same wire to the firewall from the battery or hot solenoid post? So this will power up all switched and non switched accesories? I was surprised that the whole truck is juiced up by this 1 little wire. Thanks for the reply.

 

Replace the fuse link, then try it out. Don't by-pass it.
AL.

 

OK, I have similar problems after installing a hi-torque mini starter which by passes the solenoid. The previous owner put a stock looking alternator on a serpentine system for this 302 engine but it is single wire! I never thought much about it until exchanging the alternator at the parts store & coming home finding no charge! All I use the soldenoid for now is as a junction point. So, how to wire it properly and are Ford mount single wire alternator available from NAPA or similar??? Thanks in advance!

 

If your alternator has these connections on the back of it, then you can hook it up like the diagram below. Of course you will have to buy a regulator too.

 

Thank you, this may be pretty basic also but I'm not the best at wiring. The truck has a push button to start separate from the switch so do I still run that through the solenoid even though its used only as a junction point for the rest??

 

take the alt back and have them check it for a power draw. a one wire alt can discharge the batt in a short time because it maintains a magnetic field. in a good working one wire this is only after a long time. if the alt is fine use a continuse duty solenoid that is controlled by the key switch. use a signal from the key switch to pull the solenoid that you will install between the alt and the batt.
doing this and having a volt meter in (around) the cab that you can monitor will in the long run be the most reliable and easiest way. if you go this route then you could even keep an extra solenoid around as it can come in handy for ether the starter or the alt.

 

I have never heard of having to install a relay inbetween a one wire alt and the battery. The whole idea of installing a one wire alt is to simplify the wiring, not make it more complicated.

From what I understand, the one-wire has a "self exciting" regulator that brings the alternator online by itself. The one disadvantage I have heard of this system is sometimes you have to rev the engine a little before it will automatically bring the alt online to the battery and start charging.


Don't get bogged down because the diagram shows the starter relay(solenoid). It's only used as a connection point for the battery +. If you want to hook the alt output and the "A" terminal directly to the battery +, you can.

 

let your truck sit for a week or so, with power applied to the ign swtch wire on your alt and see if your batt is low, then you will know for sure

 

Semis have used one wire alternators for years with no problems with draw down. You can also convert the older GM internally regulated alt to a single wire with the addition of a wire from the heavy terminal to one of the connections on the side of the alternator. Anyways, to answer the original question, for a one wire setup to work, there needs to be an exciter wire going hooked up to the alternator. That would be the first thing I checked. Assuming that it is hooked up, I would have it checked to make sure the voltage regulator is not shorting out or bad. As for it draining down from sitting, I have run a single wire on my 90 F250 for a year now, and other than a bad voltage regulator in the beginning have no problems with it drawing down and it is parked anywhere from 1 to 3 weeks at a time while I am gone.

 

In the configuration in the above quote, you still need the wire from the ignition switch, to the idiot light, to the GM alternator #1 terminal. This will bring the alternator "online" so it's ready for charging. So in this configuration, you would have two wires. The large output wire, and the smaller wire going to the idiot light in the dash. A true one wire has a special regulator, and it only needs one wire. I believe you can buy the special regulator and put it in a GM alternator to convert it over yourself.


This applies to what I wrote above. A true one wire is just that, one wire.

 

i did a one wire conversion on my jeep changed out the ford style alt with a delco then took apart delco got a self exciter internal regulator for it about a -$5 part put it back together mounted it in place then hooked the battery wire back up and then just disconected the wires from the reguator taped them up and out of the way works fine and simple one wire is all you need