pfloyd32086 Posted November 1, 2017 Share Posted November 1, 2017 Hi all, I just picked up an 87' Comanche long bed, 4.0, 4x4, auto. Got it for a great deal with one catch... the wiring harness is melted in about a one foot section. What are suggestions for fixing this in the most cost effective way possible? What year/years harness will work if I can find one at a junk yard? Will I need to replace the ECU as well? Can I just make a clean cut and solder new wires in? I am new to the group and would appreciate any info you guys have. Thanks! Below is a picture of the wires in question. Link to comment Share on other sites More sharing options...
Dzimm Posted November 1, 2017 Share Posted November 1, 2017 Did the PO know the cause of it melting? That would be the first thing I'd look into. What part of the harness is melted? You should be able to just cut and solder if it's only a foot but with as many wires you'd have to do, it may be easier to get a new harness. Link to comment Share on other sites More sharing options...
johnj92131 Posted November 1, 2017 Share Posted November 1, 2017 You really need to figure out WHY the harness melted. That is the real problem! Repairing/Replacing the damaged wires should come after you fix the real problem. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted November 1, 2017 Share Posted November 1, 2017 You absolutely need to figure out they why it melted, far as I know it’s unusual for a renix era jeep (87-90) to do this, was there a fire ? My phones not loading the full picture of the damage but I see something on the thread just can’t tell where it is. I’ve tried fixing cars with harness damage, unless it’s very limited in scape I’ve found it better to replace the harness with a good used part. To many gremlins to hunt down. For replacement locating a engine harness for the correct year with correct accessories is the surest fit with least hassle, you might be able to go up the years, I dunno the changes through the years.eBay and car-parts . Com and Hollander parts are search engines for used parts, it’s a pit of a pain for electrical items like this because the interchange is unknown because Jeep and others don’t really have this data in their parts catalogs .Depending where the damage is you might be able to replace the section of it by unplugging it at the factory junction ports. On the renix I’m not really sure how many sections there are. But if you have to replace the part that goes to the fuse box make sure you match the main bulkhead pattern, this might be the wrong technical term, but through the years jeep changes the that huge plug at the firewall where it connects to the dash harness and fuse box, I think much of the renix era might be the same but there no reliable information about interchange so it’d be best to stay in you year for that particular part unless you get a complete engine and dash harness together from a donor vehicle.Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
mjeff87 Posted November 1, 2017 Share Posted November 1, 2017 The Renix harness is basically two separate harnesses that come together right around the area of damage in the OP's picture. One section is from the C100 (that huge plug at the firewall where it connects to the dash harness and fuse box^^^) down along the driverside inner fender and across the vehicle @ the radiator support. A separate sub-harness plugs into it behind the driver side headlamp for the front end lighting. The other section runs from the ECU through the firewall (or C101 connector, depending on year) across the back of the firewall over to the relay center, where it connects via several flat connectors to the other harness. The ECU-end harness has a sub-harness for the TCU, which runs back through the firewall to the passenger side dash knee bolster panel. It is hardwired, not attached via connectors. Depending on where the damage is, you would have to replace one or the other sections of harness (once you figure out what caused the damage in the first place). Link to comment Share on other sites More sharing options...
Skorpyo Posted November 1, 2017 Share Posted November 1, 2017 Probably not related... but did the vehicle have converted headlights? Meaning does it have H4 bulbs instead of sealed beams? Did something outside of the wiring melt it, or are you certain it was in the wiring itself? Did the seller say if the vehicle had been sitting? Wouldn't be the first time something gnawed through wires resulting in issues like this... Definitely agree figure out what caused the melting, then fix and rewire. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted November 1, 2017 Share Posted November 1, 2017 Is it possible that battery acid melted that?Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Gene Posted November 1, 2017 Share Posted November 1, 2017 Hi pfloyd, Could you post a few more pics, including closeups, of the damaged areas? Might be able to give a better guess about what is going on if we saw more detail. Gene Link to comment Share on other sites More sharing options...
pfloyd32086 Posted November 1, 2017 Author Share Posted November 1, 2017 Unfortunately, I do not know the answer to the $100,000 question. The previous owner passed away and the guy bought it from had no knowledge. I can tell you: It has standard headlights. The relay box is not attached for some reason and wires are laying everywhere. I went to the junk yard today with no luck, just a 2000 and a 94. Thoughts? I have also attached a better picture of the damage that may help. It’s a big mess and I am a bit overwhelmed. Guess I just need to get lucky and find a harness. Link to comment Share on other sites More sharing options...
pfloyd32086 Posted November 1, 2017 Author Share Posted November 1, 2017 Link to comment Share on other sites More sharing options...
Pete M Posted November 1, 2017 Share Posted November 1, 2017 try car-part.com and search for various items for your year MJ or an XJ. the website organizes by part number so it should then find late 80s Jeeps for you and you can then go to them and see if the harness is available and acceptable. or pullapart.com lists the cars in their various yards. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted November 1, 2017 Share Posted November 1, 2017 I don't think the 87-90 had a fuse box there like the 91-up XJ/MJ did, looks the fuse relay box the Renix had is there but I'm more familiar with the 84-86 v6 and 91-94 4.0 HO XJ. Did a quick search on Hollander parts (used parts), looks like J&W may be the folks to call, they specialise in Jeeps, they also show several engine harnesses for 87 Cherokee and one is exactly a 87, 4.0 automatic 4x4, (stock # 648U) here is a link for the search https://www.hollanderparts.com/used-auto-parts/1987/jeep/cherokee/electrical/648-engine-wire-harness/648.am8287-alternate-engine-wire-harness This is the search result for the harness from that 87 stock # 648U (on car parts.com they show $250) https://www.hollanderparts.com/used-auto-parts/1987/jeep/cherokee/electrical/648-engine-wire-harness/648.am8287-alternate-engine-wire-harness/part-212717-4686-1 At car-part .com search, they don't have a listing for engine harness you have to look it up as " Electrical Part Misc and Wiring" then read the descriptions to find what you're looking for. Keep in mind you might be able to use another year but there is no guide I know of to make sure it will work. http://car-part.com P.S. Why does the font size change so much? Link to comment Share on other sites More sharing options...
carnuck Posted November 1, 2017 Share Posted November 1, 2017 I don't think the 87-90 had a fuse box there like the 91-up XJ/MJ did, looks the fuse relay box the Renix had is there but I'm more familiar with the 84-86 v6 and 91-94 4.0 HO XJ. Did a quick search on Hollander parts (used parts), looks like J&W may be the folks to call, they specialise in Jeeps, they also show several engine harnesses for 87 Cherokee and one is exactly a 87, 4.0 automatic 4x4, (stock # 648U) here is a link for the search https://www.hollanderparts.com/used-auto-parts/1987/jeep/cherokee/electrical/648-engine-wire-harness/648.am8287-alternate-engine-wire-harness This is the search result for the harness from that 87 stock # 648U (on car parts.com they show $250)https://www.hollanderparts.com/used-auto-parts/1987/jeep/cherokee/electrical/648-engine-wire-harness/648.am8287-alternate-engine-wire-harness/part-212717-4686-1 At car-part .com search, they don't have a listing for engine harness you have to look it up as " Electrical Part Misc and Wiring" then read the descriptions to find what you're looking for. Keep in mind you might be able to use another year but there is no guide I know of to make sure it will work. http://car-part.com P.S. Why does the font size change so much? Just a wild guess on the font, but there is several WYSIWYG or html codes back to back with no space between it might affect it by doubling the code. As for the wiring, when I converted my ‘88 shortbox 2wd 4.0L BA10/5 to Renix AW4/np242 I used the harness from a ‘90 XJ with that setup and removed the C101 from the circuit at the same time. The C100 pinout for the harness was the same and the transmission harness was on the engine side, but ran back through the firewall to the controller and the CPU. I don’t recall which CPU I used (I had 8 at the time) but I think it was an ‘89. The autotrans install was interrupted for about a year. I still have the engine side with relays from the 5 speed 2wd ‘88 to the C101 connector. The only problem I had was the trans didn’t shift on it’s own. Turned out the fuse holder was corroded off at the fuse, but not visible. I drove it several years after that before I started having the ignition shutoff issues at operating temp after changing the thermostat for winter. Renix years had the fuse box right where a leaky clutch master can pee on it, corroding all the terminals. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
carnuck Posted November 1, 2017 Share Posted November 1, 2017 It is the markup code that changes the font size. Quoting the post showed two Hs in brackets back to back. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted November 1, 2017 Share Posted November 1, 2017 1 hour ago, carnuck said: It is the markup code that changes the font size. Quoting the post showed two Hs in brackets back to back. Thanks. If I could see where the code was changing it I could fix it manually, I'm just not used to the real interface for this forum instead of the phone app. Link to comment Share on other sites More sharing options...
pfloyd32086 Posted November 2, 2017 Author Share Posted November 2, 2017 Ok, guys you are great! I have sourced an exact year, transmission, drivetrain, harness from car-parts. On another note does anyone have the wiring diagram for the renix 4.0? I found a previous thread that had some links to diagrams but the links were all dead. Link to comment Share on other sites More sharing options...
Ωhm Posted November 2, 2017 Share Posted November 2, 2017 1988 Electrical Manual - Comanche Link to comment Share on other sites More sharing options...
87MJTIM Posted November 2, 2017 Share Posted November 2, 2017 Get the 88 electric manual for your reference library. HOWEVER, be aware there are subtitle differences from 87 to 88. I have a paper copy of the 87 electric manual. While doing some electric work on my truck, the wiring did not match the diagrams in the 87 manual. I checked the 88 manual and it matched what I have. I found some other difference just in the configuration of part between 87 and 88. My MJ came off the line in May 87. So it was a late model year production. Jeep must have started using components designed for the 88 models. (AMC = any makers components) (Before anyone comments: I am the original owner. There have been no electrical modifications done to the truck.) Link to comment Share on other sites More sharing options...
johnj92131 Posted November 2, 2017 Share Posted November 2, 2017 Send a p.m. to fiatslug87 and ask him to send you a copy of both the 87 and 88 electric manuals. He has both in electronic form and will share. Spoiler Link to comment Share on other sites More sharing options...
pfloyd32086 Posted November 2, 2017 Author Share Posted November 2, 2017 Thank you, pm sent. Link to comment Share on other sites More sharing options...
carnuck Posted November 2, 2017 Share Posted November 2, 2017 Possibly www.oljeep.com has the Renix diagram too. Tom has all sorts of diagrams. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
carnuck Posted November 2, 2017 Share Posted November 2, 2017 Hi all, I just picked up an 87' Comanche long bed, 4.0, 4x4, auto. Got it for a great deal with one catch... the wiring harness is melted in about a one foot section. What are suggestions for fixing this in the most cost effective way possible? What year/years harness will work if I can find one at a junk yard? Will I need to replace the ECU as well? Can I just make a clean cut and solder new wires in? I am new to the group and would appreciate any info you guys have. Thanks! Below is a picture of the wires in question. The picture is just small enough to not tell if it’s rodent damage or melting or a combo. It looks like there was something hot on top or maybe they had a halogen light sitting there too long. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
johnj92131 Posted November 2, 2017 Share Posted November 2, 2017 Clean each and every connection as you go as you replace the harness. One other thing you need to do when you replace the harness: Do all of Cruiser54's Renix electrical fixes. http://cruiser54.com/ Link to comment Share on other sites More sharing options...
carnuck Posted November 2, 2017 Share Posted November 2, 2017 100% agree on that. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
pfloyd32086 Posted November 2, 2017 Author Share Posted November 2, 2017 More photos of the carnage.More photos of the carnage. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now