Here's the Durango alternator swap documentation for anybody who wants to do it in an XJ or MJ.
The physical compatibility and arrangements for this has been well covered but I wanted mostly to cover the electrical part of the swap. And if you do it, you may have all lights pulsing at idle. I did, and here's how I fixed it, thanks to one of (inventor of the REM II) Nick's friends...
For stock alternator location:
- There are plenty of 5.9L Durango alternator swap guides out there, mostly for 91 and up. Those don't require a bracketry swap, as the alternator case mounting holes are the same, just a larger case. Those require some shaving and cutting to accommodate the larger case, and that's well covered on the internet.
- For 87-90 Renix Jeeps equipped with a CS-130 case alternator, the brackets are entirely incompatible. This will require swapping to the 91-98 alternator brackets and likely a belt change.
For top mount, non-A/C equipped jeeps:
- 87-90 will require swapping to a later 91-98 A/C compressor mounting bracket for most top mount conversions. No one I've seen makes anything to mount the later alternators on a Renix A/C compressor bracket.
- 91-92 MJ & 91-98 XJ already have the later A/C bracket, ready to go. I got a USA-made top mount alternator adapter kit from SpeedShop505, but they're not making this as of March 2026. Plenty of other copies out there. Belt change is required.
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Larger Images of Electrical Diagrams here: ---> Durango Alt Wiring
Electrical:
Going from this (p.24 1988 Comanche Electrical Manual):
To this:
Complete regulator and relay harness:
Harness Explanation:
All lights pulsing at idle - common issue when doing this swap! The yellow field wire on the original Renix alternator connector is usually the indicated switched 12V source. However, it comes all the way from the ignition switch, through Splice D, through bulkhead C100, through Splice R if you have A/C, through Splice E, through connector C335, and finally to C205 at the alternator. This is a run of about 10-11 feet! Plenty of noise and voltage drop opportunities. Nick R (
NickInTimeFilms) and a buddy of his did this swap in a YouTube video:
The 89 XJ in the video already has the 91-98 A/C compressor bracket due to a previous HO-era A/C swap, and they're ditching that in the video, but that's not the point. The wiring is (11:24 - 18:12). In the comments someone asked if the lights pulsed at idle, and the owner, tylermus, replied that he'd added a relay next to the battery to eliminate the issue. So that's why I did this, and it worked great.
There also needs to be a ground wire from the regulator body to body ground. I added a large ground on the passenger side to mirror the one on the driver's side fender well (G106), so I tied into that. The 20A fuse between the relay and battery is optional, I did without.
I unplugged C335 and tucked away the side for the alternator harness. Rather than cut anything, I headed to the local boneyard looking for 88-94 Chevy TBI V8 trucks. It's the brown wire connector you unplug when setting the distributor base timing on those trucks. On the firewall under the PDC cover if the truck still has it. I got the Field wire 1&2 connector from a random Jeep/ Chrysler vehicle a while back, don't recall exactly which (easy to find).
External Regulator kit is from Alternator Man / alternatorparts.com, kit
ERCK. Setup and explanation video from the Alternator Man himself here:
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One more note: if you have a "Standard"/ dummy instrument cluster...
NOTE: I'm 90+% certain this is correct
for trucks with the "Standard"/ indicator light cluster.
