Bronco charging problem

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Dec 30, 2003 | 11:53 AM

Matt_W

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From: CT USA

Bronco charging problem

I have a 77 bronco and it wont stop full fielding. All the components are new, ie voltage reg, alternator, solinoid. I think the problem is in the voltage regulator circuit. There is nothing going to the "S" terminal on the voltage regulator. The truck has an amp gauge but its one of those that measures drop so its not part of the circuit so I dont think that has anything to do with the problem. I have tried wiring the S terminal to the Stator terminal on the alternator with no luck and i have also tried jumping the S terminal with the A terminal (Which is how i think the origional was done) with no change either. If i disconnect the voltage regulator completely i get about 12.8 volts instead of the near 16 volts i get charging when i have it connected. Also there is a constant large draw when the voltage regulator plugged in even with the key off. Anyone have any bright ideas? Am i missing something obvious? Any help would be great
I dont think its the voltage regulator ground either cause i tried grounding it directly to the battery with no change.

Matt

Dec 30, 2003 | 12:14 PM

Franklin2

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From: Virginia

Here's how it should be wired. The choke wire is optional.

Dec 30, 2003 | 01:24 PM

Mike W

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From: Central Kali

If the wiring is correct, it has to be the regulator.

Dec 30, 2003 | 01:35 PM

Matt_W

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From: CT USA

Thanks for the info...two more questions... where should the I terminal go? There is a wire that goes from the regulator to the ignition module (the 2 wire plug on the duraspark 2 module). Is this the wire that is hot with the key? also is there any way to test a voltage regulator. I have a bunch of them lying around but i dont know if any of them are good. I figured that was good since i recently bought it new (but it was from autozone so who knows)

Dec 30, 2003 | 02:18 PM

Mike W

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From: Central Kali

I am not sure of the ign module wire. The I terminal connection is not needed if you go by the diagram. It is used with the idiot light setup.

You can test the old regulators by hooking them up temporaraly on the truck. Be sure they are grounded. Hook the field term to the alt fld term. Jumper +12 to the S term and the A term to +12. See if the bat will go to about 14 volts.

This will not check idiot light operation. It involves a few more circuits in the regulator.

Dec 30, 2003 | 02:33 PM

Mike W

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From: Central Kali

Also unless you get a short circuit in the alternator field, there is little chance of damaging a regulator. They are pretty robust devices. I take them apart to see how they work.

Dec 30, 2003 | 02:40 PM

Matt_W

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From: CT USA

Still having problems.....I decided to go back to square 1. Right now the voltage regulator is plugged in but in my origional bronco harness there is nothing connected to the "S" terminal (theres an empty space on the plug). Is this possible? has ford ever had a setup with nothing connected to the "S" terminal on their regulator? Second could perhaps i have gotten the wrong voltage regulator? Maybe the S and I terminals are reversed on my voltage regulator? Did Ford make two different kinds with different terminal locations? But if this is the case shouldnt have jumping the S and I terminals given me controlled charging?
I also tested the voltage regulator and it passed both tests it lists for them in the motor manual so i think that component is ok.

If some of the wiring diagrams I am reading are correct i see that the S termnial somewhere goes into the starter switch? Where would be a good place to pick this wire up in the engine compartment if i have to rewire? Which wire is it on the Duraspark II module?

Thanks for all the help so far.