27_east Posted October 23, 2020 Share Posted October 23, 2020 I have been browsing this site and cruiser54's as well but haven't seen anything about this. I have a 1989 Jeep Comanche with manual AX-15 Transmission and am trying to hunt down an engine side wire harness. I found a guy who has a harness from an 1989 Cherokee but his is an auto. His harness has a 2nd firewall plug that goes into the interior for the TCM to plug in under the dash. My original harness never had that 2nd firewall plug because it had no TCM. (or I assume?) Anyone know if his auto harness work on my MJ? Can that 2nd firewall plug be left unplugged? Or will it run if the TCM is plugged in and he includes it with the sale. Thank you in advance. Link to comment Share on other sites More sharing options...
Torq_Shep Posted October 23, 2020 Share Posted October 23, 2020 It will work but you will need to jump 2 pins on that plug (can't remember the exact two but they are right next to each other). However, my 1989 had serious mouse damage on the engine harness, I pulled it out, degreased it, rehabbed it, and retaped the harness in a weekend. That is another option. Edit: Hey look 200 posts =P Link to comment Share on other sites More sharing options...
27_east Posted October 23, 2020 Author Share Posted October 23, 2020 Thanks! That was helpful, I found a write up from a guy that did a auto to manual swap and he showed the NSS jumped. Its a gamble but i just want to get the truck running. Link to comment Share on other sites More sharing options...
Torq_Shep Posted October 23, 2020 Share Posted October 23, 2020 For reference (search users =P): Experts may correct me... Harnesses are the same (or at least compatible) for Auto and Manual 1987-1988 4.0 harness are compatible with each other and compatible with 89-90 with a C101 connector delete. 1989-1990 4.0 harness are compatible with each other and may be compatible with 87-88 but you will not have a C101 connector anymore 1991-1992 4.0 harness are only compatible with 1991-1995? Cherokees and 1991/92 Comanches. Link to comment Share on other sites More sharing options...
89 MJ Posted October 23, 2020 Share Posted October 23, 2020 3 minutes ago, Torq_Shep said: For reference (search users =P): Experts may correct me... Harnesses are the same (or at least compatible) for Auto and Manual 1987-1988 4.0 harness are compatible with each other and compatible with 89-90 with a C101 connector delete. 1989-1990 4.0 harness are compatible with each other and may be compatible with 87-88 but you will not have a C101 connector anymore 1991-1992 4.0 harness are only compatible with 1991-1995? Cherokees and 1991/92 Comanches. Looks correct to me! Link to comment Share on other sites More sharing options...
27_east Posted October 23, 2020 Author Share Posted October 23, 2020 Great thanks everyone for the insight! Link to comment Share on other sites More sharing options...
Swampy Posted October 26, 2020 Share Posted October 26, 2020 It will work. I used a '96 auto xj to swap my jeep, used all the wiring for the xj and it runs and drives fine with my ax15 Link to comment Share on other sites More sharing options...
27_east Posted November 6, 2020 Author Share Posted November 6, 2020 Thank you to everyone who replied. Wanted to follow up in case someone wants to do this as well. I can confirm the automatic harness will work. Just hooked it up and the truck runs. The one important step is that you jump the NSS. (Black connector next to the gray connector) It will not run if it is not jumped. The bottom middle pins are what were jumped. (Shown in photo) Link to comment Share on other sites More sharing options...
Torq_Shep Posted November 6, 2020 Share Posted November 6, 2020 (edited) Disregard =P Edited November 6, 2020 by Torq_Shep Found what I was looking for Link to comment Share on other sites More sharing options...
Swampy Posted November 17, 2020 Share Posted November 17, 2020 On 11/6/2020 at 8:40 AM, 27_east said: Thank you to everyone who replied. Wanted to follow up in case someone wants to do this as well. I can confirm the automatic harness will work. Just hooked it up and the truck runs. The one important step is that you jump the NSS. (Black connector next to the gray connector) It will not run if it is not jumped. The bottom middle pins are what were jumped. (Shown in photo) I haven't jumped the wires on my 96 harness and it runs and starts up fine. Link to comment Share on other sites More sharing options...
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