IROC Wrangler

I just got done swapping a 305 TPI motor out of a Firebird Formula into my Wrangler and have one thing left to do.... wire up the alternator. There are three wires coming from it: One brown wire from a 2 wire plug into the top, one red wire from that same plug and a red wire coming from a ring on the back of the alternator. My understanding is that the brown wire needs some resistance to keep the alt from burning itself up, and that a 12 volt lightbulb wired to a keyed ignition source will do the trick. I've also heard that the other two wires (both red wires just go to the battery.

Would this be a sufficint way to wire this up? I've tried looking at the factory wiring diagram and the useless Haynes manual, and neither has been any real help.

Thanks in advance!

Matt

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90 Wrangler with Firebird Formula TPI 305, Chevy granny low 4 speed tranny and Scout Dana44 axles.

Tim Burgess

The lug on the back of the alternator is the output of the alternator, and should be connected directly to the battery + lead through a heavy gauge (10 gauge) stranded wire.

The other two small wires in the plug connector control the alternator. The red wire is a voltage sense wire that should go to a battery (hot all the time) wire at some point in the harness, not near the battery, to sense the system voltage at that point. If you hook it up directly to the battery, the voltage drop through the harness will not be compensated for, so the net system voltage will be slightly lower. The brown wire powers the alternator when the ignition is turned on. The resistance wire used in some applications is to keep the engine from continuing to run after the ign is turned off by blocking the current feedback path with a high resistance. If the brown wire is plain copper wire, connect it to ignition power that is isolated from ignition power that goes to the ECM & ign coil. In other words, when the ignition switch is in the off position, the brown alternator wire may not connect to the wire that powers the engine & ign coil, or the engine will continue to run after the ign switch is turned to the off position.

Tim

IROC Wrangler

Thanks, dude! That is PRECISELY what I was looking for! Great board! This has been SO helpful to me!

By the way, I have a F*rd starter solenoid in my Jeep and was wondering if it would make enough difference in the voltage to wire the red wire from the 2 prong connector to the hot side of the solenoid. That is pretty close to the battery, but not right on it.

Thanks again!

Matt

Satan87Z28

Hey Matt, I like Jeeps and am always trying to talk my friends whom almost everyone has one to put a camaro motor in it. Got any pics of your Jeep?

Tim Burgess

The red "voltage sense" wire normally does connect to the large lug on the (GM style)starter solenoid, which is where the fusible links that supply power to the different systems connect, as well. So, I'd connect it to where ever the power distribution point is, (the point where one large diameter wire feeds a group of smaller diameter wires) which is probably the large input lug on the solenoid you are talking about.

Tim

Calico

I'll use this to wire up my alternator! very useful