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97+ conversion on a 86 MJ (new questions.)

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Well I stumbled across a real nice 99 XJ in the JY today and I couldn't resist and bought the front clip and fenders. I've got all the old off and the new fenders on but, right off the bat I notice I forgot the fender brackets for the front :mad: . Well that aside, I figured I'd test fit the header and get the brackets tomorrow. Now I knew before I started that the 86 is probably the worst choice because of the differences in the header, but it looks like a BFH is in my future.


Long story short, I need some help from someone that has done the conversion on a 86. Where and what did you have to modify on the front firewall/rad support? Pictures would be worth a thousand words :D

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Well I answered my own question and will post up pic's tomorrow. I have a different question that I hope someone can point me in the right direction.


I want to use the 97+ wiring harness and yes I no I can use the old one but it's crap and I don't want to. I've searched high and low on a right up or anything about how to use the 97+ wiring and splice into the old. If I know want wires are what on both that will help but all my diagrams seem to leave out a wire or two. I plan on splicing the new plug to a spare old plug, that way I can plug or unplug whenever I need to.


Have to get this done by the morning so the kid can drive it. :roll:

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So did you get it all handled?




So here are the pic's of the ordeal.


Old stuff off.



For the 97+ header to fit the 86 MJ with the 2.5l, a few minor mods are needed. At first I thought about just using the BFH to adjust the radiator support/firewall, but after one smack, I changed my mind and figured it would be easier to mod the header. Just have to cut out just a little bit on the inner top of the headlight bucket and a small part of the inner lip of the headlight bucket.



I started off small and just kept fitting and cutting till it was right. Another place that needs adjustment is right next to the airbox inlet. I drilled a hole to allow the headlight adjustment screw to fit.



On top of the fenders where the hood rubber stops go also needs to be drill out because their location changed just a little.



Then it just takes some time to fit and adjust till you have everything lined up good and tighten it all down. This took a long time as I found out during this mod that the truck had been wrecked before and nothing was straight. Then throw the new bumper on, which was the easiest thing during this mod, and presto, you have a 97+ front on your 86 MJ.



To handle the wiring, I figured I'd just use the newer harness on the header, and using a spare connector, make a short adaptor harness to join the two.



Once you figure out what is what on both headers, this is pretty straight forward.



Was a hole just in the right place to keep this out of the way of the rad overflow bottle.



Best thing about doing the wiring this way, is the ease of unplugging the harness if needed, you don't need to hack up your engine harness, and best of all, you get the alternating turn signal and side marker mod for free.


Will still need to mod the top header support to fit the radiator support. Basically it will need a notch cutout for the spring and spacers to fill the inch difference in the height.



Also need to get a side mount prop rod for the hood as the 86 had a front one.


I happy with it but wish I had known about the previous damage to the MJ. I probably would have not done it had I known. Anyway, I'll get the rest done and get it all cleaned up and post the pic's in the build thread.


I guess this kind of qualifies as a DIY thread, so if you want to move it Pete, please feel free.


And yes, I know I'm missing the "e" in Jeep. :nanner:



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Keep up the good work and pics, now lets get workin on the other one :popcorn:


You really know how to hurt a guy.




But you are very right. I had a bad feeling when I got this one, this might happen. The problem is that I can get instant satisfaction working on the 86 because I'm not that picky with it. Unlike the Wild build, it takes a lot to get just a little ahead.


I'll try harder. :thumbsup:



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When I installed a new complete header panel on my 87 MJ (out of a 94? XJ), I also got the alternating turn signal for free. But I lost my factory fog light wiring in the process. I kept the old harness to splice in the fog lights if I ever get a new pair.

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This needs to be in the DIY !!! Nice writeup... If I ever decide to do this I'm going to use your writeup.

I do have one question though.....

In this picture I don't 100% understand what you did...


That's just it, I didn't do anything, yet. :brows:


What needs to happen there is put in the bracket that bolts to the header and then bolts onto the rad support/firewall (whatever that piece is called). The one that was in ther was in two parts on either side of the hood catch in the middle, plus the left side held the hood prop rod. The 97+ is a single long one. I'll need to notch out a place on the new one for the hood spring and make something to compensate for the inch difference(gap) between the new bracket and rad support. It will make more sense when I get it done a post a pic.


Also just as a reminder to all, this is just for the 86 as the 87-92 should be a direct fit with out modding the header.



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That's just it, I didn't do anything, yet. :brows:


Also just as a reminder to all, this is just for the 86 as the 87-92 should be a direct fit with out modding the header.




Oh $#!t now you tell me!!!! :roll:


lol but really I was like huh :redX:


I have a 4.0 too so I'm sure theres something to the radiator too...

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  • 4 weeks later...
  • 1 year later...
  • 1 year later...
  • 1 year later...

Isn't there a diagram floating around somewhere of the wiring on the older vs. newer header panel plugs? Any idea where I might find that?

I know you post that in '10 but just for reference for anyone who happens to find this thread



Hooked up mine today and realized that the high beam and low beam wires are switched on the 97+ harness list I put up here is the correct way (corrections in bold):


I had this coppied down from somewhere:

Which wiring diagram? I have an 89 and 99 FSM and here are the headlight harness colors:


Connector C106 driver's side main harness to headlight harness looking at the back of the headlight side connector with the tab on top Pin 1 is on the right top pin 8 is on the right bottom:


1 empty

2 red - Left headlight HIGH beam power

3 light green - Left turn signal power

4 black - Right headlight park/turn light ground

5 empty

6 red/orange - Right headlight HIGH beam power

7 brown - Left parking light power

8 light blue (w/ fog lights only) - Fog light power (to bulb)

9 violet - Left headlight LOW beam power

10 tan - Right turn signal power

11 black - Left headlight park/turn light ground

12 red (w/ fog lights only) - Fog light power out (to relay)

13 violet/red - Right headlight LOW beam power

14 dark green/yellow - Right parking light power


1989 headlight wiring. Main harness to headlight harness connector on driver's side. Looking at the back of the connector on the headlight harness side with the 'ears' on the bottom, Pin 1 is left top and pin 6 is right top.


1 empty

2 white - headlight high beam power

3 grey - left turn signal power

4 dark blue - parking light power

5 black - ground

6 red (w/ fog lights only) - fog lamp relay power in

7 light green - headlight low beam power

8 brown - right turn signal power

9 empty

10 light green - (w/ fog lights only) to fog light relay signal power


Hope this helps.





97+ harness first, 97- harness second:


1 empty

2 red------------------------------2 white

3 light green-----------------------3 grey

4 black----------------------------5 black

5 empty

6 red/orange-----------------------2 white

7 brown---------------------------4 dark blue

8 light blue (fog lights)

9 violet----------------------------7 light green

10 tan-----------------------------8 brown

11 black---------------------------5 black

12 red (fog lights)

13 violet/red ----------------------7 light green

14 dark green/yellow---------------4 dark blue


Hopefully the colors are the same. only problem I could see running into is that on the 97+ headlight harness the headlights low and high beams are separated left and right so each function has its own wire so there are 4 wires doing the 2 functions of the headlight. you are now condensing the 4 wires into 2 wires of the same gauge.



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  • 2 months later...

I'm going backwards here.  I did a 88' to 98' conversion and I'm still using the 88' front end.  I'm trying to connect the 98' wiring to the 88'.  I'm even game to just connect the light sockets to the factory wiring.  It sounds easy enough but when I did so it does not work.  One side or the other will work but seems like I'm always missing a side marker light.  Would a burned out bulb in the rear wiring do this?  Does it matter that I'm connecting less lights than before?


I don't really understand how the two wire side marker lights are supposed to work with no ground wire?  It the signal alternated from hot to ground or something?

Does anyone have a wiring diagram or chart to address this? The factory 89' harness was half mangled in a accident so I'm having to do some guess work here...

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  • 6 years later...
6 hours ago, vw jeep guy said:

came out nice..........great job. I did the same and did not get the front fender angle brackets. I was able to find a guy selling parts in town with white angles which I needed. 


Just so you know, this thread was last commented on 7 years ago. 

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