Internal Voltage Regulator

[Deanj]

One thing after another.

I converted my car to an alternator 2 years ago. After driving 10 miles and returning home yesterday, my '60 Hardtop's GEN light came on bright as day. I shut the engine down and restarted. The light was off, then came on, and went off.

I drove another 6 miles noticing the alternator belt was squealing easily, but everything else seemed normal. So today I tightened the belt and checked the battery and alternator. The battery read 12.5V engine off, and the alternator produced 18.5V with the engine running!

I take it the internal voltage regulator took a dive. Are these easy to replace on a 10Si?

Dean

[simplyconnected]

The Ford regulators are easier because you don't have to take the case apart. But, no big deal. Not only are these regulators easy to change, they're also cheap. I see someone is selling them out of Florida for $6 to your door. I don't know if your alt was bought new but you may want to change brushes as well.

Here's a youtube video showing how to assemble the 10SI - CLICK HERE

[Deanj]

Surprise! O’Reillys lifetime warranted the alternator. I still had to find a longer standard belt tensioning bolt, and drill the case so the old generator bolt would pass through the case to the rear bracket.

I home right? Seems after the voltage regulator failed and I didn’t know it had failed yet, I fried the 80 amp fuse holder and fuse. The fuse never blew, but it “fused” itself to the holder-just as I was ready to start and test. I found an 80 amp fuse holder at Auto Sound since no auto parts stores had these. Fabrication city.

Worked perfectly. I started her up and with most electrics on the voltage registered 14.4!

Dean

[simplyconnected]

Your setup isn't right at all. A GM 10SI only puts out 60-amps. You're melting an 80-amp fuse to the holder. That's doesn't happen from a bad voltage regulator.

Can you draw a diagram of your alternator, battery and starter solenoid wiring? You don't have a subscription so you can't post pictures directly but you can send it to me: simplyconnected@aol.com
Also include a few pictures of your setup. - Dave

[Deanj]

Dave, I'll send what I have.

But...The positive battery cable is connected to the front post of the solenoid. The fused 4 ga wire connects from the rear alternator "bat" terminal to the front solenoid post. A second smaller red wire connects from the front post of the solenoid to the alternator plug connection terminal. The remaining white wire from that same plug was extended and connected to the yellow wire. There are 2 remaining wires that where taped up and not connected to anything.

I thought I mentioned I'm running 14.4V now with the replacement alternator. The meltdown occurred, before testing the alternator, while driving the car 6 miles during which the alternator was putting out 18V.

Dean

[jopizz]

It sounds like you have it wired correctly. You can just put a ring terminal on the small red wire from the harness and connect it to the BAT terminal of the alternator. You don't need to run it all the way to the solenoid. How many amps is your alternator?

John

[simplyconnected]

..I thought I mentioned I'm running 14.4V now with the replacement alternator. The meltdown occurred, before testing the alternator, while driving the car 6 miles during which the alternator was putting out 18V...

Yes, I read that. 18-volts from a 60-amp alternator does not melt 80-amp fuses. Something else is very wrong. Once I see the pictures I am sure I will have more questions. - Dave

[Deanj]

It sounds like you have it wired correctly. You can just put a ring terminal on the small red wire from the harness and connect it to the BAT terminal of the alternator. You don't need to run it all the way to the solenoid. How many amps is your alternator?

John

John, it's a 63 amp 10si. Coincidental because I was just thinking I could have attached the red battery wire to the rear "bat" terminal. I just connected it to the existing wire at the solenoid.

Dean

[Deanj]

Yes, I read that. 18-volts from a 60-amp alternator does not melt 80-amp fuses. Something else is very wrong. Once I see the pictures I am sure I will have more questions. - Dave

There's only one other wire to consider since there's 3 wires. 2 hot going to the solenoid, and one white going to ? I believe I attached that to the yellow wire that goes to the GEN light. That left one ground wire on the generator and I didn't connect anything to that.

How does everything else work correctly?

Dean

[jopizz]

There's only one other wire to consider since there's 3 wires. 2 hot going to the solenoid, and one white going to ? I believe I attached that to the yellow wire that goes to the GEN light. That left one ground wire on the generator and I didn't connect anything to that.

How does everything else work correctly?

Dean

That's correct. The white wire is for the GEN light which you can attach to the existing yellow wire that used to go to the old voltage regulator. Like Dave I'm confused as to how a bad voltage regulator can melt the fuse holder.

John

[Deanj]

I know during the 6 miles I drove with the bad regulator I turned everything on. When I checked the alternator the next day it read 18+ and 17+ volts with everything on but the brake lights.

My former Honda and Pontiac mechanic friend thinks it's probable, and he's seen melted fuses before.

Dean

I unwrapped the wires and found the white wire connected to the light colored wire routed from the front of the car. The black wire was tapped off. That accounts for all 3 wires. How can I get the GEN light if the remaining white wire wasn't connected to the correct wire?

[simplyconnected]

As promised, I will post your pictures and some of my comments but it might take two posts. First, a picture of how a GM 10SI alt should be wired. Notice a few things; 1) the fuse is normally mounted on the fender apron, not dangling between the car body and alt, 2) there is a resistor connected around your GEN light in case the bulb burns out so the alt remains energized when the key is on.

GM uses two 'sense' wires. One is called Field 1 and it is white. The other, 'Sense 2' is red. Ford only uses one and it goes to the gen light through the key switch.

The fuse you used is for high frequency audio. You should be using a BUSS Mega Fuse, mounted on your fender apron, close to the starter solenoid. Fuses melt because the wire or is too small or connections are not tight. Mega Fuses bolt down and never melt.

If I do a wire splice, it will be with a crimp connector, mashed down as tight as possible so all the metals become one. Solder is not acceptable in 'automotive' or especially in high current splices.

I know I asked you for more/better pictures but you said, you taped the wires together so no more pics... I want to see your ground wire as it is equally important to the heavy battery wire.

[Deanj]

Which ground wire? The battery ground is attached to the rear of the alternator mount bolt just like it grounded to the generator. The alternator, I assumed, grounds on its own mounting. I didn’t use the bolt on the rear of the alternator.

Dean

[simplyconnected]

GM uses the #2 or red sense wire to make up for resistance losses, usually from splices and current carrying metals. The more resistance, the more voltage drops. Steel is a terrible conductor and voltage drop becomes much more apparent when current is high. (This is when things heat up.)

As John pointed out, that 'sense' red wire can be connected to the BATT post on the alternator but that defeats GM's intentions.

Let's suppose the red wire is loose or not connected, so the alternator does not sense 'feedback voltage' coming back from the battery. The alternator will try outputting all it has in order to make 14-volts appear on that white wire. That means it will correctly output 18-volts if the white wire is not tightly connected. This is probably what happened in your case.

You use the steel bracket for your ground and I cannot tell if the size of your ground wire exceeds the size of your alt's BATT wire, as it should. So again, the red wire which is a 'sense' wire, is used by the alt to compensate for all resistance in your charging circuit by raising the output voltage of the alternator. The ground wire's resistance is certainly part of the electrical loop between the alt and the battery. I hope I explained this well enough for everyone to understand. The GM system is good and it works on millions of cars but it is slightly different from the electrical philosophy at Ford. If you have questions, please ask them.

Ford OEM alternators don't have those three power wires, they have only two which are the heavy battery wire and the skinny GEN Light wire. The ground wire is a given... - Dave

EDIT: Got ahead of myself and my red/white colors. As per the diagram, white goes to the GEN light, which turns on the alt. Red is the 'sense' wire that alters alternator output voltage.

[Deanj]

It sounds like you have it wired correctly. You can just put a ring terminal on the small red wire from the harness and connect it to the BAT terminal of the alternator. You don't need to run it all the way to the solenoid. How many amps is your alternator?

John

Dave, I thought John said the small red wire could be attached to the rear output terminal. Would that serve as extra protection since it isn't fused my way?

But isn't the battery ground to the alternator sufficient? Therefore the alternator is grounded well since the battery seems to work with this set-up?

Dean

Dean