jeepcj7304;129049 wrote
It is a AC Delco 12SI alternator. I have the power lug on the back running to the battery and a small wire spliced in that jumps to the plastic clip and into the alternator. Then there is a white wire that I believe is the excite wire it has voltage with the key on. There is no dummy light in my jeep for this that i know of but i will double check and im unsure of any resistor on this wire. It seemed to work previously with the old motor. but something could have got switched i guess. I dont think it has anything to due with the fan since i pulled it as soon as i got the alternator working and pulled the fuse from the main power for the fan weeks ago.
This could be your issue. There needs to be a resistance in the excite wire. This is usually provided by the battery indicator lamp in the dash. The alternator will not charge otherwise. In one wire alternators, this wiring is performed internally and no other connections are required other than the charge wire to the battery.
The spade terminals on the alternator are labeled (1) and (2). #2 is on the left if looking at the rear of the alternator.
In most some applications the load sense wire (#2) is looped to the charge output as yours is. This works fine if your battery is very close to the alt. This works fine in modern OEM applications as most high loads originate near the battery +12vdc terminal. If you have a fan relay mouted close and fed from teh battery this will be fine for you.
As peak loads move farther from the battery, it takes more of a draw to tell the alternator to turn up the juice. I have a rear mounted battery. I have a +12vdc stud under the dash (fed from the bat) that feeds all my electrical needs. So this is where I routed the load sense wire. I have the charge output from the alt directly to the battery. This really only becomes a concern when you stray to far from factory specs.
I feel your problem is in the excite wiring.
There are some simple tests you can do.
#1) Start your engine. Remove the +12VDC connector from your battery. If the engine dies, there is an alternator problem.
#2) Rig up some wire with a female spade connector on one end. Put a 12v light bulb in the middle (an old marker light works well) Make sure the wire is long enough to reach your battery. Put an alligator clip on the other end.
Connect the spade connector to #1 on the alt. Connect the other end to the +12V at the battery. The light should be on.
(If not on your battery is dead, the bulb is burnt or the volt regulator in the alt is junk)
Start the engine. Light should go out. If not, rev the engine a little then it should go out. If the light is out, your alt should be charging. If the light stays on, you have alternator problems.
And if you really must know.... Go here
http://www.rowand.net/Shop/Tech/AlternatorConversions.htm
for more information on alternators than you will ever WANT to know.
