Internally regulated alternator help

[Maladd]

I have installed a new 12 si internally regulated alternator on my 1963 C10 with dash charge light. The alternator is not charging the battery and the charge light stays on while the truck is running. I currently have it wired as follows.

I have the brown wire (to ignition/light) from the cab hooked to pin 1 (the pin furthest from the engine block w/ driver side mounting).

I have a hot wire from the distribution block wired to pin 2.

I have a hot wire from the distribution block wired to pin on the back of the alternator.

I am showing ~12v across the battery terminals with truck running, or not running. Does not change even at higher revs.

My charge light is off with the key off. On with key on and when running.

Am I missing something here, or should it be working?

Thanks,
Jeff

[Kenfuzed]

Here is a basic drawing of a 12si schematic. There needs to be a heavy gauge wire (12R) direct from terminal B on the alternator to battery. I'm not personally familiar with the 63 but on my 66 this is similar to how I rewired mine. Not sure I follow your description but it doesn't seem like you have anything directly sending current to the battery. I have a 12ga wire going from Alt to my horn relay (junction), and from the horn relay to the battery.

[Heater63]

Maladd, that wiring sounds correct for a 3 wire hookup. Make sure your alternator is working, and your charge wire is correct gauge.

I use a voltmeter with my 12SI and not a charging light. My experience with a charging light is only on generators. My 12SI runs right at 14 volts. I have a junction point near but not on my starter solenoid. Both the sense (pin 2) and the Charging feed run to that junction, just like in Kenfuzed diagram.

review on www.madelectrical.com, everything you need about 3 wire SI alternators is there.

[jtrichard]

Sounds like you are wired right , what is the history on the alt? new/used/rebuilt?

[Kenfuzed]

Hi Jeff forgot to ask you, what is the voltage at the alternator's output with the engine running? At high idle you should see between 13.6 and 14.6 volts at the alternator output (BAT). If have this voltage at the alternator you can move on to diagnosing the wiring itself.

[Maladd]

I was unsure how to test the alternator, so I tested off the pin in the back to the chassis and showed no voltage, but I doubt that's right since it should at least show the battery voltage.

The alternator is a new one, but I bought it in August and just now got the truck together and running.

[Maladd]

I did change the wiring for the distributor/fuel pump a bit early on. The distributor and fuel pump were getting power from the starter and spliced together. I ran a dedicated wire from a circuit on the fuse box to each. I don't really see how that could have affected the alt. though.

[jtrichard]

http://i.imgur.com/2tJeU.jpg

Here is a pic of an alt. you don't need the diode as you are hooking / hooked that wire to the light ..With engine/key OFF check for voltage at Stud/Bolt that the 10ga. is hooked to then check again with engine running

[Maladd]

Thanks everyone so far!!!

Found I had made a stupid mistake and didn't notice a bend in the wire going to Pin 2. It was actually the old ground wire from the external regulator.

I took and jumped from pin 2 to the pin on the back of the alternator. The pin on the back of the alternator is fed from the horn relay (which is fed from the battery).

The blue wire is still hooked to pin #1.

Now I have no charge light on the dash when key is on (engine off), but have the charge light lit when the engine is running.

The good news is that I AM showing over 14 volts on the alternator when running, but only 12.2 on the battery.

Currently my external regulator is as follows:

Top and bottom wires are cut at the old regulator, 2nd from top (black wire is cut since I trimmed the brown wire and ran to pin #1). Red wire (3rd from top) is still hooked up to the horn relay.

Good news is that my alternator is good. Bad news is that I'm lost on the wiring now LOL.

[jtrichard]

This might help you
http://67-72chevytrucks.com/vboard/s...d.php?t=119379

[Maladd]

Been working off of that post. Going to try replacing the wire from my battery to relay tomorrow. Can't hurt.

Thanks for the help :-)

[Kenfuzed]

Originally Posted by Maladd

Thanks everyone so far!!!

Found I had made a stupid mistake and didn't notice a bend in the wire going to Pin 2. It was actually the old ground wire from the external regulator.

I took and jumped from pin 2 to the pin on the back of the alternator. The pin on the back of the alternator is fed from the horn relay (which is fed from the battery).

The blue wire is still hooked to pin #1.

Now I have no charge light on the dash when key is on (engine off), but have the charge light lit when the engine is running.

The good news is that I AM showing over 14 volts on the alternator when running, but only 12.2 on the battery.

Currently my external regulator is as follows:

Top and bottom wires are cut at the old regulator, 2nd from top (black wire is cut since I trimmed the brown wire and ran to pin #1). Red wire (3rd from top) is still hooked up to the horn relay.

Good news is that my alternator is good. Bad news is that I'm lost on the wiring now LOL.

If you have 14v at the alternator and a feed wire (10ga) going from alternator output post to the horn relay, and then to the battery (10ga), then you should also have 14v at the battery. The horn relay is actually only a junction point so there should not be any voltage drop. I would check that you have a good 10ga wire along that route.

[vince1]

As my wiring had been pretty messed up I previously had run a #8 ga. with fusible link from battery to horn relay junction. To hook up a 10si I disconnected the connector from the regulator, and at the connector jumpered the brown to the blue. At the alternator blue to #1, old #12 ga. output wire to #2 and run a new #10 ga. from alternator output back to the horn relay junction.

[Maladd]

Finally got the battery charging. The wire from the battery to the junction was undersized. Thanks for all the help!!

I need to do a little Google Fu and see why my dummy light is acting backwards though. It's lighting while engine is running (gets brighter with revs) and is not on when key is on with engine off.

Main thing is that the charging system is working :-)

[stellar]

fuse