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Mar 6, 2005 | 07:49 PM

baitmaster

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From: nevada

alternator question

Just installed a 1 wire Ford type alt on my '72. Everything seems to working OK, but am wondering where or what the large red wire with fusible link has to be hooked up to. It was from the regulator harness. My ammeter doesnt seem to be registering anything. the 3 wire plug was all hooked to hot side of solenoid, and the 2 wire plug (green & brown, and yellow is not hooked to anything.

Mar 7, 2005 | 06:25 PM

Franklin2

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From: Virginia

How did you hook up the new alternator? Did you run a new wire from the alt to the battery +?

Mar 8, 2005 | 08:18 PM

baitmaster

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From: nevada

wire hookups

Yes, ran a new battery cable from hot side alt to pos battery post. Prob overkill on wire size, but I had it and the ends are factory, so I didnt have to fab up a wire for it. Not sure about large red wire with fusible link as to what it hooks to if anything. It is a single wire that was coming off of the old regulator mass of wires. All accesories work, except ammeter. Dont want to burn anything up if I hook it to that. Was wondering if I could hook a battery charger clip to it, and give it about 10 amps to see if needle on ammeter would register anything. So far the new 100 amp alt seems to working fine, the lights dont dim anymore at idle, and I';m running a electric fan that pulls 28 amps.

Mar 8, 2005 | 09:59 PM

rebocardo

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From: Atlanta GA

> f I could hook a battery charger clip to it, and give it about 10 amps to see if
> needle on ammeter would register anything

First, that is a very bad idea to do with any battery charger.

Second, the color code is different (does yours have a stripe?) I guess between my 71 and your 72. But, I show that fusible link as going to circuit 904 which leads to the voltage reg. for the dash panel. Not something I would nuke.

Mar 8, 2005 | 10:31 PM

Franklin2

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From: Virginia

I am thinking this wire with the fusible link was the original alternator output wire. It's larger than the other original wires correct?

This would explain why the ammeter doesn't work anymore. The ammeter is a very sensitive voltmeter that reads a "shunt" that is installed in the original output wire.

Does the original ammeter even go high enough to read the full output of the new alternator?

You could possibly unwind the original harness to extract the red wire with the fusible link. Somewhere along the length of the red wire you will probably find a weird splice with two smaller wires coming off either side. The two small wires go to the ammeter, and the shunt is in the middle. If you wanted to experiment, you could try cutting this section out and installing it in your new alternator output wire to try to make the old ammeter work.

Mar 9, 2005 | 07:37 PM

baitmaster

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From: nevada

big red wire

Yes this a large solid red wire with the smaller fusible link. It came from the reg loom and headed for the firewall. I seem to remember that the last time I had the dash open there was some big red wires running to the ammeter. I forgot to mention that I have an aftermarket ammeter, using the same wires that were hooked to the original. This is a 100amp alt, and the ammeter reads to 60amps. Never thought about having to change it, I guess someone makes a larger capacity gauge? So maybe I'll hook that baby up and if it burns the gauge out, i'll find a bigger one.

Mar 9, 2005 | 09:21 PM

Franklin2

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From: Virginia

Quote:

I forgot to mention that I have an aftermarket ammeter, using the same wires that were hooked to the original.

Be careful. The above doesn't make any sense to me, so watch out when you start hooking things up.

The original factory ammeter was as I said before, a very very small voltmeter with amp numbers on the face or "D" and "C" for charge and discharge. It had very small wires that run from a shunt in the original wiring. In no way shape or form would a regular aftermarket ammeter work with this set-up.

The aftermarket ammeters I am familiar with have two large studs coming out the back of the ammeter. Full current from the system has to run through this type of guage, so very large wires have to be run to and from the guage. And if you have this set-up, it should be obvious that someone added these wires, since they would not have been original.

Here is a diagram of how an aftermarket ammeter should be hooked up.