I am looking into a ax15 swap from a 99 into a 97 (with aw4) for a buddy. I have been reading through different posts and it seems some are saying that the wiring harness needs swapped? at least the engine harness? and then it seems others ( including the pdf in the faq section here) are saying just to swap the pcm... can anybody confirm this for me? My buddy wrecked the 99 so we have access to a full donor just need to know what all we need. The goal is to do with without any check engine codes. thanks!
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97 ax15 swap ??
- Thread starter 2CC4x4
- Start date
Ivan
I Jeep, therefore, I am..
- Location
- Greensboro, Ga
I believe you'll need to swap over the PCM as well, so be sure to grab it too....
I'm aware of that.... thats not my question at all but thanks anyway!
- Location
- Rainy side of Washington
I believe the 99 ECU will work with your 97 harness, but not 100% sure. You'll want to get FSMs for both years and compare the pin-outs for the two. The most important part is - count the O2 sensors on both jeeps, make sure they are the same, there should be one upstream and one downstream on each. Everything else *should* be mostly the same between a 97 and a 99, though I'm sure there are minor wiring harness differences.
You got lucky, one year earlier on the recipient or one year later on the donor and it would not have worked at all.
Everything mechanically should simply bolt up. You'll need the trans, hydraulics, flywheel, flywheel bolts (the AW4 flexplate bolts are shorter), an FC69907 pilot bearing (iirc), all clutch parts, the pedal assembly, the transfer case shifter linkage and the bracket off the transmission from the donor, the transmission itself of course, possibly the crossmember, and the driveshafts. I'm sure there are other things I'm forgetting.
The centers of the holes that must be drilled for the clutch master to mount to the firewall are all center punched, but from the interior side, so you will have to get real comfortable under the dash or drop / disassemble portions of the dash to get to it properly. Drilling the main hole can be kinda annoying, I ended up drilling a series of smaller holes around the periphery of the actual hole and then dremeled between them and cleaned up with a half round file.
You'll want to unplug the TCU (it may or may not set off a CEL otherwise - I don't think the manual ECU will pay attention to the TCU, but not sure) and will need to jump the NSS harness for the P/N pins so that the jeep can be started. I ended up cutting a connector off an old junk NSS I had and connecting the pins so that I had a "dongle" to plug in instead of hacking up the engine bay harness. That connector also has the pins for the reverse light switch (part of the NSS on the autos) so I used a bunch of wire and the reverse light connector off a manual wiring harness to build a custom NSS to reverse light + P/N bypass cable.
You got lucky, one year earlier on the recipient or one year later on the donor and it would not have worked at all.
Everything mechanically should simply bolt up. You'll need the trans, hydraulics, flywheel, flywheel bolts (the AW4 flexplate bolts are shorter), an FC69907 pilot bearing (iirc), all clutch parts, the pedal assembly, the transfer case shifter linkage and the bracket off the transmission from the donor, the transmission itself of course, possibly the crossmember, and the driveshafts. I'm sure there are other things I'm forgetting.
The centers of the holes that must be drilled for the clutch master to mount to the firewall are all center punched, but from the interior side, so you will have to get real comfortable under the dash or drop / disassemble portions of the dash to get to it properly. Drilling the main hole can be kinda annoying, I ended up drilling a series of smaller holes around the periphery of the actual hole and then dremeled between them and cleaned up with a half round file.
You'll want to unplug the TCU (it may or may not set off a CEL otherwise - I don't think the manual ECU will pay attention to the TCU, but not sure) and will need to jump the NSS harness for the P/N pins so that the jeep can be started. I ended up cutting a connector off an old junk NSS I had and connecting the pins so that I had a "dongle" to plug in instead of hacking up the engine bay harness. That connector also has the pins for the reverse light switch (part of the NSS on the autos) so I used a bunch of wire and the reverse light connector off a manual wiring harness to build a custom NSS to reverse light + P/N bypass cable.
Last edited:
- Location
- Rainy side of Washington
Nope. But fortunately it's pretty easy to build the harness I did - I'm just really OCD about wiring.
Cut the connector off the NSS. Two of the pins (not sure which, looking it up shortly) you connect together. Another two pins, you connect to the two pin reverse light switch on the new transmission.
edit:
Jumper the P/N pins - pin 7 and pin 8
R pins - pin 3 and pin 6 - go to the reverse light switch on the AX15.
The wiring harness colors only apply to the side of the harness that is attached to the body, but they are:
pin 7 = BK/WT
pin 8 = BK
pin 3 = WT
pin 6 = BR/LG
These colors came from my '98 FSM so there is a chance they won't match the 97 or 99 harnesses. Again, those are colors on the connector the one you want mates to, so this is really only useful as sanity checking info.
Cut the connector off the NSS. Two of the pins (not sure which, looking it up shortly) you connect together. Another two pins, you connect to the two pin reverse light switch on the new transmission.
edit:
Jumper the P/N pins - pin 7 and pin 8
R pins - pin 3 and pin 6 - go to the reverse light switch on the AX15.
The wiring harness colors only apply to the side of the harness that is attached to the body, but they are:
pin 7 = BK/WT
pin 8 = BK
pin 3 = WT
pin 6 = BR/LG
These colors came from my '98 FSM so there is a chance they won't match the 97 or 99 harnesses. Again, those are colors on the connector the one you want mates to, so this is really only useful as sanity checking info.
Last edited:
- Location
- Rainy side of Washington
yes - edited last post for pin numbers and other nonsense you'll need.
Cut it off on the side away from the engine harness - ideally, just cut the harness off the side of the NSS right down on the passenger side of the AW4. Then you'll need a bare minimum of wire to make it reach the reverse light switch.
I use this method because it leaves zero "hacks" in the main wiring harness, which simplifies replacement parts getting and keeps everything way neater.
Cut it off on the side away from the engine harness - ideally, just cut the harness off the side of the NSS right down on the passenger side of the AW4. Then you'll need a bare minimum of wire to make it reach the reverse light switch.
I use this method because it leaves zero "hacks" in the main wiring harness, which simplifies replacement parts getting and keeps everything way neater.
excellent man thanks for all the help!!! this sounds much easier than swapping the harnesses. but I guess if we get a cel code we will have to swap them. Although I don't see why we would. the faq walk through that i read from naxja said to order a pcm for your year with manual tranny programming... but i don't think that should be necessary since the pcm should swap from 99 to 97.
- Location
- Rainy side of Washington
No problem, hopefully everything goes smoothly for you.
I think that the ECU should work out fine. Let us know if you get a CEL and hopefully I or someone else can figure out why you are getting one.
I think that the ECU should work out fine. Let us know if you get a CEL and hopefully I or someone else can figure out why you are getting one.
