What does this electrical box do?

[bmxmon]

After along time of ignoring my mustangs electrical problem, i've decided to finally deal with it. My problem is with this box i believe. When I start my mustang, the volts will run low (around 11) and my "GEN" light will stay on until I rev my engine up to around 25-3k, then the volts will jump to about 13-14, the GEN light will turn off and it will be fine at any rpm. When i then turn off my car, after the engine stops my GEN light will come on and stay on, until i disconnect the battery. (Though on occassion it will come back on after i reconnect it, if done right away) I believe it is this box that has gone haywire, since it clicks when i disconnect the battery. It just recently started doing the low volts thing on startup, requiring me to rev it. (Which makes me think my alternator is going bad also) Thanks for any info, I hate electrical systems....

[Rev]

That's the voltage regulater. Just replace it. Probably $15-20. Should come with directions for installation. All you have to do is polarize it before rehooking the connections.

Rev

[bmxmon]

Sounds good, thanks rev

[Gearhead999]

Yep, the voltage regulator is sticking. Common failure of them, in the day. Get a new one, make sure you polarize it.

[bmxmon]

Well, went to napa and they gave me one, was the wrong one. As it turned out, the voltage regulator in there is for a generator (so the napa guy tells me...) and the new ones are for alternators, which i have in my car. So now I have this voltage regulator for an alternator, and the wire connector is coming in on tuesday. What wires will I need to splice to go where? My new VR has 4 posts, an I, A, S, and F. The old one only has 3, but there is another connector just hanging there, goes to that coil. (I believe you can see it in one of the pics) Thanks again guys.
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Oh, and by the way, for some reason the instructions in my new one said not to try to polarize it, whats up with that?

[Kisner]

If it was me, and you don't mind spending $45, I'd just order the correct voltage regulator from Mustangs Unlimited or NPD. I always hated splicing wires.

[bmxmon]

Well, this is supposed to be the right voltage regulator for my alternator, the voltage regulator in there before was supposed to be for a generator (along with the wiring) Yeah, im not a fan of splicing wires either, but i dont really see a way around it this time.

[Kisner]

Oh O.K. I understand now. See if this attached wiring schematic might help.

[Rev]

Don't think you need to splice any wires. It's just as Kisner's diagram shows. If you use an indicator light, then you will use the I terminal (wire goes to the I terminal on the starter relay). If you use an ampmeter, then you don't need to hook anything to the I terminal on the voltage regulator.

Rev

[bmxmon]

Ah, ic, awesome wiring schematic, thanks alot kisner. I actually will have to splice the wires as the ends are different (where it connects to the voltage regulator), but it shouldnt be a big deal. Thanks so much guys, you were all a big help.