The Stovebolt Site Forums The Shop Area The Electrical Bay I goofed up the alternator wiring

I switched my '59 from generator to alternator, but apparently messed up the wiring harness install. The alternator is putting out a good charge (reads a solid 14) but the battery isn't getting that charge.

Here's a pic of the alternator:
http://i35.photobucket.com/albums/d...20Pickup/20161012_135603_zps70nnntbb.jpg

Can I assume that the heavier gauge red wire coming out of the back (there's also a lighter gauge red wire in the same black nipple) is the power supply? If so, can I just run it directly to the terminal on the starter? (I've got a stomp starter.)

Ideally I'd trace that wire down to find out where it's now going, but it's inside a wrapped bundle, and for now I just need a truck that runs and doesn't strand me when the battery dies, like happened today.

Or am I wrong about that wire and/or where it should go?

If its like my 59 the heavy gauge wire runs to the starter or to the batt. the lighter wire goes to the volt meter on the dash. If you are getting 14v at the alt and not at the batt try a jumper from the alt to the batt. use a volt meter to look at the battery . read it with eng off then start and see if the voltage goes up. if it does you are charging. put on the headlights and see if the volts drop a little. That style alt needs a exciter charge to get it working. Where are you getting that?

Did you eliminate the voltage regulator on the firewall as part of the conversion? If so, the ARM wire and the BAT wire at the regulator should have been spliced together. Does the truck have an ammeter or an idiot light "NO Charge" indicator?

Yes, you can run a temporary wire (10 GA or larger) from the back of the alternator to the battery cable connection at the starter to get the battery charging, but you really need to wring out the wiring soon. Be sure to insulate the big wire you remove from the back of the alternator- - - -it could short out and cause problems. Don't cut anything away, just tape the connector off for now.
Jerry

I have a set of Dakota under-dash gauges - temp, oil pressure, and ammeter. That's where I'm getting my 14a reading. The voltage regulator on the firewall was eliminated because this alternator has an internal regulator.

So unless someone screams "FOUL" I'll run a 10 GA wire to the batt. terminal on the starter and take readings at the battery. And then yes, make work of tracking down where the other end of that harness wire is. (I suspect I ran it to the dash, but hopefully not)

I should make it clear that the truck died because it was running off the battery, and when the battery was drained...nothing.

Here's how I ran the three wire alternator on my '57 using the original harness. This might help you to sort it out.

I left the original voltage regulator as a dummy. The BAT terminal is used as a junction stud. The battery feed wire, gauge wire, large wire from the alternator and sensing wire from the alternator all attach to this terminal. (In my case, also the A/C primary wire.)

The exciter wire from the alternator is connected to the ignition side of the ignition resistor on the firewall. Since I do not have an idiot light, I soldered a diode into this wire at the alternator connector end so that the engine would turn off when the key is turned off. (If you search this site, someone recently posted that they purchased an adapter plug with the diode on eBay...plugs into the alternator, then the harness plugs into the adapter.)

Wiring as above allows the sensor wire to work as it should by sensing the load away from the alternator.

Matt

Huh???

style

OK, style. But "needs an exciter charge" is over my learning curve. Don't know what that means and what I should have/do.

Pathway. sorry for the spell ck.

Update:

I traced the heavier gauge wire from the alternator to....it seems to run to the (aftermarket) headlight switch, and from there to the dash amp gauge. That gauge has been replaced by a Dakota set of 3 mounted under the dash, so I don't need the dash version anymore.

I've never encountered a vehicle without a fuse block, and this headlight switch seems to me an odd way to route electrical. So again, please forgive my ignorance. Here's where I am now:

Again, I clearly should and do not have a wire from the alternator to the starter (or battery). That is, unless this headlight switch system includes that connection.

Before I disconnect the present heavy gauge wire from the alternator, tape it off, and run one directly from alternator to starter, what will I lose by eliminating that run to the headlight switch?

I did all of this work over a year ago, and then all kinds of life issues meant the project got set aside. Thus, my memory of the work I did and connections I made is fuzzy. But does that alt-to-headlight wire provide power to everything else??

The headlights and the ignition switch I believe. That wire feeds everything if I remember correctly. I will check how I wired my 59 and check the shop manual for a wire diagram.

I can't find the shop book with the wire diagrams. Reading back over your post, are you using an aftermarket wire harness? If so you need to find the wire diagram for that harness. It looks like you have two red wires connected to the post on the rear of the alt., and the white plug has two wires. The brown wire on the white plug excites the alt., (12 volt power from ignition switch to turn on alt.). Get a volt meter and check when the ignition is on if there is 12 volts to that wire.If not it won't charge. With the engine running you should have 14 volts at the battery.

I know the alt is producing power b/c the Dakota gauge set shows 14A of output. So while that exciter bit is something I don't understand that part must be correct or I wouldn't have output. It just isn't getting where it should go.

And yes, I used an aftermarket harness I got with the bracket. We've moved to a different state since that happened and I have NO idea where that diagram is...or if there even was one.

Amps and volts are two different things. When running, the alt. should be putting out more than 14 amps. I'm not talking down to you, but you have to check the voltage at the battery. That little brown wire is what makes the alt. work, If it doesn't have 12 volt at that point, the battery will not charge. With the engine running take the volt meter and put the black wire to a good ground (engine block) and touch the red wire to the post on the back of the alt. what voltage do you have? Should be 12-14 volts, if it is, do as 59chevy36 and hot rod lincoln said run a jumper from the post on the back of the alt. to the battery. Check the voltage with the volt meter at the battery, should be between 12 and 14 volts. If it is problem fixed, with the exception of finding out where those wires under the dash are going. You don't want a loose wire shorting something out.

You do NOT need to worry about talking down to me! Half of being smart is knowing when you're dumb, and when it comes to auto electrical I'm all of dumb. And thankful for patient tutelage.

We're in the middle of the storm you've heard about that's hitting WA and OR, so tomorrow, or Monday if it takes that long, I'll do as you advise and check the alternator output.

But do I need that alternator wire running to the headlight switch?

I still have the factory wire harness ,and that wire feeds everything in the truck. It is probably different with an aftermarket harness.

I think Pathway could use some on site hands on help. Any 'bolters' in his area to get him on the right path. I don't want him to melt his harness or lose interest because of the frustration. Everyone has some knowledge is one area or another. Me, I get 'glassy eyed' when I open up a transmission.

Good idea, Beltfed. Pathway, I'm in Gilbert. Send me a PM if you want to get together or talk it through.

Working from memory here, but I am pretty sure that the dash gauge output wire feeds everything except the direct feed from the battery to the starter. The headlight switch would be fed after the dash gauge, not before, with the stock harness.

I can show you how the same three wire alternator is hooked up to my '57 if you want. You can use that as a starting point. I have a copy of the stock wiring diagram in my manual.

Matt

Maybellene...
A year ago we moved to Oregon, west of Eugene. Gilbert used to be close, but it's a 2-day drive now. I need to change my info here; will go do that now.