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Unread 06-14-2012, 10:25 AM   #1
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1972 C104 
Join Date: May 2012
Location: Clovis, Ca
Posts: 11
4.0 alternator wiring

Installed a 93 4.0 into my 72 Jeep Commando. I need some help adapting my 72 wiring to the 93 alternator. I am using a Hesco wiring harness which has a field wire that I need to hook up. But what original wires from the Commando do I need to connect to the 93 alt? And where on the 93 alt? I have had no luck finding a wiring diagram for the 93 on the net.Really appreciate any help!!

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Unread 06-16-2012, 07:37 PM   #2
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1982 CJ8 
Join Date: Nov 2011
Location: Clearwater, Florida
Posts: 336
I have the wiring diagram from the FSM for a 1993 XJ, Cherokee in pdf format. PM me if you're interested.
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Unread 06-20-2012, 12:05 PM   #3
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1999 XJ Cherokee 
Join Date: Apr 2011
Location: Ceiba, PR
Posts: 879
The 72 had a separate regulator. The '93 has the regulator built into the ECM. The field wire you are referring to is the regulator wire. SOOOOOOOO on my '95 the regulator/field is pin 20 on the ECM. The other wire goes to ground.
The large output wire goes to the PDC, then to the battery. The field voltage can't be successfully measured at is a Pulse Width Modulated signal to better control the alternator. A #4 wire can be added to the alternator to run to the frame if one isn't provided.


Jim W
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