Voltage Regulator Problem

[buckn' bronc]

I have a '73 and I am experiencing voltage regulator problems. The Bronco used to be my fathers and it had a fire under the dash some amount of years ago, and the wiring system had to be changed. I bring this up because I do not know if anything was upgraded at this point or not, but lets get to the point. The voltage regulator on the truck has four pins labeled I, A, S,F. As the truck sits now(and it was working this way), there is no wire going to "I", but two yellow wires going into the "A" prong. One of these yellow wires goes into the cab of the truck and one of the wires is connected to a metal,cylindrical object that is bolted to the firewall and is roughly the size of a AA battery (little larger). The "S" is hooked up to an orange wire and the "F" is a green and black wire. If I use my old voltage regulator and beat on it for a while eventually the truck will start but I just bought a new one and the truck won't start.

 

[Bully Bob]

"As the truck sits now(and it was working this way), there is no wire going to I"

This is correct.

"..two yellow wires going into the "A" prong. One of these yellow wires goes into the cab of the truck and one of the wires is connected to a metal,cylindrical object that is bolted to the firewall and is roughly the size of a AA battery"

Correct., except one yellow goes to the starter solenoid (front post) not to cab. CHECK THAT

"S" goes thru the firewall to the ignition switch.

"F" goes to back of alternator.

However I don't think this is the starting problem. This is the "charging" circuit.

Check your "ignition". Dizzy., coil., key switch., getting spark..?

HTH

B

 

[buckn' bronc]

"As the truck sits now(and it was working this way), there is no wire going to I"

This is correct.

"..two yellow wires going into the "A" prong. One of these yellow wires goes into the cab of the truck and one of the wires is connected to a metal,cylindrical object that is bolted to the firewall and is roughly the size of a AA battery"

Correct., except one yellow goes to the starter solenoid (front post) not to cab. CHECK THAT

"S" goes thru the firewall to the ignition switch.

"F" goes to back of alternator.

However I don't think this is the starting problem. This is the "charging" circuit.

Check your "ignition". Dizzy., coil., key switch., getting spark..?

HTH

B

Right on, that is a lot of good information. Sometimes the truck just doesn't start at all, almost like there is no battery in it, then I mess with the VR and it seems to work.

What is that metal cylindrical piece that is plugged into "A"

 

[Rons beast]

The piece the size of a AA battery is probably a radio static supressor/ noise filter. Of the 2 wires from "A" terminal on the regulator, One should go to the starter relay, As Bully said. The other should go to the "B" connection on the alternator. ( it may be spliced to a blk/red wire there).

There should be a wire from the "I" (ignition/indicator)terminal to the iginition switch in the cab, and the alternator indicator.

The orange wire should be on the "F" (field)terminal of the regulator. and the same on the alternator.

The green and black should be on the "S" (stator) terminal of the reg. and same for the alt.

I think there is some miswiring on your rig. Probably the startin problem, because the ignition circuit is wired in a "round about" way.

Best bet is to get a wiring diagram, and trace each circuit, or you could just be chacing gremlins for a long time.

It really isn't hard, just time consuming. take each wire and circuit by its self, and take your time....and invite a good friend to help. (your choice of liquid enticement is up to you.)

Good luck, and let us know how you make out.

 

[Bully Bob]

Being your wires were burned., who knows what wires/colors were used for replacement.

The #'s below are the wire routing...., the letters are the location on the V. Reg.

Same Reg. for '66-'77 however some additional wires were added to the plug that goes on the Reg. in later yrs.

---------------------I-- (un-used unless you have a GEN. light on panel---newer models)

152 & 152A ----A Orig. yellow

904----------------S Orig. green/red stripe

35-----------------F Orig. White

Also; colors may have changed over the yrs.

 

[buckn' bronc]

Thank you guys, this is a lot of good info. I will report back on the progress