Externally regulated altenator on '90 Comanche

[atxg3]

Hi all,

I'm fixing my buddy's truck while he's out of town as explained in another post I made on this forum. He swapped in a 2001 XJ Engine and Trans and  into his '90 Comanche. The wiring is the original comanches. I took a look and seems like he still has his XJ alternator. 

 

The comanche alternator wiring is this l shaped plug here:

His alternator requires a plug that will fit his alternator as seen here:

 

I am not certain at all that he has a voltage regulator already installed, so just to be on the safe side, has anyone made this conversion before or has a suggestion for a conversion kit for this?

 

Thanks all in advance.

[jeeptec1]

If your buddy is still running the 90 Comanche wiring and computer use an alternator for a 90 Comanche. The 87 to 90 XJ and MJ use a alternator with an internal regulator. The 91-92 MJ and 91 and Later XJ use an external regular which is built into the PCM. Does the vehicle run?


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[atxg3]

23 minutes ago, jeeptec1 said:

If your buddy is still running the 90 Comanche wiring and computer use an alternator for a 90 Comanche. The 87 to 90 XJ and MJ use a alternator with an internal regulator. The 91-92 MJ and 91 and Later XJ use an external regular which is built into the PCM. Does the vehicle run?

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Thanks for the info, that's indeed what I did assume. Yes the vehicle does start and run, given the battery does not receive a charge due to the connector not connected to the alternator. 

[mnkyboy]

Do some research on converting it to an external regulator, there's lots of write ups and even several You tube videos on how to do it.

 

It's a pretty common swap on the newer Jeeps, when the one in the ECU dies, it is a lot cheaper to convert it to external rather than buy a new ECU so lots of people go that route.

You can find kits online or piece it together yourself to save a few bucks.