Alternator Charging/Exciter Wire Issues

THEMADTYPH00N

THEMADTYPH00N

Active member
I've recently fired up a new build on my Typhoon and I have ran into a problem with the alternator not charging.

At first I thought the alternator may have gone bad. I took it to a local rebuild shop and it was verified that it was working properly. Next I thought that possibly the powder coated alternator bracket was not properly grounded to the block. It was, however I cleaned all of the mounting points anyway just to ensure a good ground. Also for trouble shooting purposes, hooked up a temporarily ground wire from the alternator case to the block just to ensure good ground. Nothing changed.

Next I looked at the plug from the engine harness. It has two wires, a tan/white that has 12v when the ignition is on and a brown wire that (if I'm reading the diagram correctly) goes to the battery light in the dash. I thought maybe I was not getting good contact, so I removed both terminals from the harness connector and slid them onto their correct prongs on the alternator. What I've discovered is that when the exciter wire (tan/white) is hooked up by itself, the alternator works and I get a steady 14.6v. However as soon as the brown wire is hooked up the alternator will stop charging.

The other weird thing is the battery light never comes on whether the brown wire is hooked up or not. I'm not ruling out that the bulb may be burned out as this truck has been sitting for awhile.

Any help would be greatly appreciated.
 
Don W.

Don W.

Stab it and steer it
Re: Alternator Charging/Exciter Wire Issues

First, no offense, but how do you know the alt is not charging?

I don't think you have a "bat" light. At least the Sy doesn't. The wire that is hot with the key is what "excites" the alt. The brown wire would be the light if you had one. Even if you don't it's not needed for the alt to function.

Don't you have a volt meter on the dash? What does it do? Key off? Motor running?

Check the output term at the alt with a volt meter. It should read bat voltage when the key of off and then 14v or so with the motor running. Maybe one or both fuseable links are blown. (Bear in mind I don't have a Ty elec manual.)

"fired up a new build on my Typhoon" leads me to think you forgot something. Have you changed the wiring in any way. (Thinking of a Sy don't forget) Is the wire from the bat to the alt there?
 
THEMADTYPH00N

THEMADTYPH00N

Active member
Re: Alternator Charging/Exciter Wire Issues

Don W. said:
First, no offense, but how do you know the alt is not charging?

I don't think you have a "bat" light. At least the Sy doesn't. The wire that is hot with the key is what "excites" the alt. The brown wire would be the light if you had one. Even if you don't it's not needed for the alt to function.

Don't you have a volt meter on the dash? What does it do? Key off? Motor running?

Check the output term at the alt with a volt meter. It should read bat voltage when the key of off and then 14v or so with the motor running. Maybe one or both fuseable links are blown. (Bear in mind I don't have a Ty elec manual.)

"fired up a new build on my Typhoon" leads me to think you forgot something. Have you changed the wiring in any way. (Thinking of a Sy don't forget) Is the wire from the bat to the alt there?
Click to expand...

No offense taken, I guess I wasn't entirely clear. I'm measuring the voltage with a Fluke off the stud on back of the alternator. With the truck running I only get 12.2v with both wires hooked up. As soon as the brown wire is disconnected I get 14.6. The volt meter on the dash follows what I'm seeing with the Fluke, as does Datamaster. I also confirm that tan/white has 12v to it as soon as the ignition is on and has nothing with the ignition off.

You are correct that there is no battery light in the dash. Guess that shows how longs its been since I've drove this thing lol. But that leaves me wondering where does that brown wire go?

I don't believe the fusible links have nothing to do with it. Those are power to pretty much everything the harness touches and the truck wouldn't run without them. Nothing is wiring has changed.

The short fix could be to leave the brown wire off, but I'm just wondering what changed.
 
DaveP

DaveP

Active member
Re: Alternator Charging/Exciter Wire Issues

The brown wire does nothing. It is not hooked to anything. It ends at C100, with a blank on the IP side,
The other wire should be pink/wht. It should be hooked to the "I" terminal on the regulator. Look along the edge of the connector, and you will find little letters. Should be P-L-I-S. Could be P-L-I/F-S. if you have a P-L-F-S, this may be the problem, but if it works hooked up as below, don't worry about it,

Hook up the one wire that has 12V on it with the key = on to the "I" terminal, and call it done.
 
THEMADTYPH00N

THEMADTYPH00N

Active member
Re: Alternator Charging/Exciter Wire Issues

DaveP said:
The brown wire does nothing. It is not hooked to anything. It ends at C100, with a blank on the IP side,
The other wire should be pink/wht. It should be hooked to the "I" terminal on the regulator. Look along the edge of the connector, and you will find little letters. Should be P-L-I-S. Could be P-L-I/F-S. if you have a P-L-F-S, this may be the problem, but if it works hooked up as below, don't worry about it,

Hook up the one wire that has 12V on it with the key = on to the "I" terminal, and call it done.
Click to expand...

The connector is labeled PLFS and I believe that's the problem as the pink wire was not landed on the "I" terminal on the alternator. I switched it around and now everything work perfect. Thanks for the help Dave & Don!
 
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