Bob89manche Posted December 16, 2019 Share Posted December 16, 2019 I’ve worked my way through cruiser’s list and am still hitting a wall. 89 mj 4.0 6cyl auto. Problem started as “car keeps running after key is removed and lock cylinder switched to “”off”” position”. Upon further inspection, everything gets power when the battery is connected except for radio, accessory, and cab lights. Replaced ignition switch,coil,ICM, starter relay, o2 relay, fuel pump relay, latch relay,ballast resistor, battery + and - cables, all duct tape covered splices cleaned and properly wrapped, all connectors cleaned, c101 cleaned, grounds cleaned and/or replaced. If I disconnect, from the battery post of the starter relay, the loop connector with green fuse link to 3 red wires and/or the loop connector with both green and orange fuse link to individual corresponding red wires, power does not reach the previously affected systems. If all relays removed, ignition switch disconnected, oil and battery lights in instrument cluster still illuminate. I’ve searched for broken wires, burned tape/ connectors. If you remove the ECU the dash batt and oil lights still illuminate. Color me stumped. Should add that I have unplugged the alternator to eliminate it as the culprit as well. Idk if this forum is still used, but fingers crossed someone can help shine some light on this poor lost soul. The truck only has 140kmiles. Thanks All, Bob Link to comment Share on other sites More sharing options...
JMO413 Posted December 16, 2019 Share Posted December 16, 2019 You definitely have a short to power somewhere. Mine was behind the fuse box. mj1988electricalmanual_(1).pdf This is the 88 electrical manual should be very close on a 89. Link to comment Share on other sites More sharing options...
eaglescout526 Posted December 16, 2019 Share Posted December 16, 2019 35 minutes ago, Bob89manche said: Idk if this forum is still used This forum is active everyday. Maybe no activity for a few hours at a time but its pretty active. But JMO is probably right. Theres probably a short somewhere that's still giving you power where there shouldn't be power. Link to comment Share on other sites More sharing options...
Ωhm Posted December 16, 2019 Share Posted December 16, 2019 With KEY OFF and everything connected, take voltage reading on D2_4. Should read 0vdc. Link to comment Share on other sites More sharing options...
Dzimm Posted December 17, 2019 Share Posted December 17, 2019 I had this happen to me once (the staying running when the key was removed) when my battery was failing in my XJ. I was having weird electrical issues for a couple weeks and then for another week after until the battery died entirely. Link to comment Share on other sites More sharing options...
Eagle Posted December 17, 2019 Share Posted December 17, 2019 Back in my racing days I created the same problem by accident. I had an AMC Javelin that I autocrossed. After being state runner-up in class two years in a row and then winning the class the next year, I wanted to try some real road racing, and I settled on the New England hillclimb circuit. I pulled out the back seat and installed a roll bar, then I decided if I was going to be at risk of falling off a mountain that a kill switch might be a good idea. I had the wiring diagrams. I cut into a circuit somewhere, wired in my switch, fired it up and then hit the kill switch to test it. All that happened was the headlights got brighter. I wish I could remember the details, because it might help you. Basically, I hadn't killed the ignition, all I had done was to take the battery out of the circuit so the car was running on direct alternator. So I undid whatever I had done, and came up with an alternate arrangement for the kill switch. Is the wiring in your MJ all original, or had it been "improved" by some previous owner? Link to comment Share on other sites More sharing options...
Bob89manche Posted December 20, 2019 Author Share Posted December 20, 2019 On 12/17/2019 at 12:29 AM, Eagle said: Back in my racing days I created the same problem by accident. I had an AMC Javelin that I autocrossed. After being state runner-up in class two years in a row and then winning the class the next year, I wanted to try some real road racing, and I settled on the New England hillclimb circuit. I pulled out the back seat and installed a roll bar, then I decided if I was going to be at risk of falling off a mountain that a kill switch might be a good idea. I had the wiring diagrams. I cut into a circuit somewhere, wired in my switch, fired it up and then hit the kill switch to test it. All that happened was the headlights got brighter. I wish I could remember the details, because it might help you. Basically, I hadn't killed the ignition, all I had done was to take the battery out of the circuit so the car was running on direct alternator. So I undid whatever I had done, and came up with an alternate arrangement for the kill switch. Is the wiring in your MJ all original, or had it been "improved" by some previous owner? Wiring is all in tact as original. New radio is the only thing that has changed. It has to be one of the 7 yellow wires split off of a single clamp. Link to comment Share on other sites More sharing options...
Ωhm Posted December 22, 2019 Share Posted December 22, 2019 On 12/20/2019 at 10:40 AM, Bob89manche said: It has to be one of the 7 yellow wires split off of a single clamp. Yes, if D2_4 showed voltage (B+ Hot at all times) with KEY OFF. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 8, 2020 Author Share Posted January 8, 2020 So I’ve gotten a little further with this after the holidays. I have found a conglomeration of Black ground wires connected together right by the MAP sensor similar to the yellow wires that give power to the ignition system. I have found a completely bare wire (looks like throttle cable) soldered to the ground connection leading to TBD. I have stopped cutting hot wires to the system and started cutting grounds. Definitely power bleeding into the ground system of wires. Can’t find a good engine harness replacement. Going to search junkyards and trace this bare ground wire to see if it yields any results. Thanks for all the help, guys Link to comment Share on other sites More sharing options...
OldManComanche Posted January 9, 2020 Share Posted January 9, 2020 What about pulling fuses out 1 at a time to see if you could isolate a circuit causing the problem. The wiring on all of the 3 Comanches I have had came with hacked up wiring. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 18 minutes ago, OldManComanche said: What about pulling fuses out 1 at a time to see if you could isolate a circuit causing the problem. The wiring on all of the 3 Comanches I have had came with hacked up wiring. Checked off the list to no avail. Link to comment Share on other sites More sharing options...
Ωhm Posted January 9, 2020 Share Posted January 9, 2020 Yes or No. Does D2_4 have voltage (B+ Hot at all times) with KEY OFF? Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 50 minutes ago, Ωhm said: Yes or No. Does D2_4 have voltage (B+ Hot at all times) with KEY OFF? Yes. When I cut the wire delivering power to D2_4, the system still receives power. When I cut the ground, power no longer is delivered Link to comment Share on other sites More sharing options...
Ωhm Posted January 9, 2020 Share Posted January 9, 2020 Disconnect both battery cables. Measure continuity between D2_4 and D1_5. Do you have continuity (0Ω's)? Stop cutting the wires. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 19 hours ago, Ωhm said: Disconnect both battery cables. Measure continuity between D2_4 and D1_5. Do you have continuity (0Ω's)? Stop cutting the wires. Reading 00.6 ohms Link to comment Share on other sites More sharing options...
Ωhm Posted January 9, 2020 Share Posted January 9, 2020 19 hours ago, Ωhm said: Disconnect both battery cables. Measure continuity between D2_4 and D1_5. Do you have continuity (0Ω's)? Take the same measurement except this time disconnect C103. Back towards the firewall. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 33 minutes ago, Ωhm said: Take the same measurement except this time disconnect C103. Back towards the firewall. Uploaded photos for clarification. There are 2 multi pin connectors by the heater control valve no change when disconnected but I don’t think these were either c103 to begin with. The second photo look like the diagram, but isn’t very close to the rear firewall. I did see change when this one was disconnected. Went from the original reading up to 2.4 ohms. I didn’t see any other straight 6 pin connectors near here, but it’s dark in Indianapolis tonight. Link to comment Share on other sites More sharing options...
Ωhm Posted January 9, 2020 Share Posted January 9, 2020 Forget I mentioned the firewall. Its gotta be the second photo. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 1 minute ago, Ωhm said: Forget I mentioned the firewall. Its gotta be the second photo. Resistance did change when that connector was DC’d. From 00.6 to 2.4 Link to comment Share on other sites More sharing options...
Ωhm Posted January 9, 2020 Share Posted January 9, 2020 It seems you got a Red wire touching a Yellow wire in the Engine Control Harness. Backtrack wires from D1_5 and D2_4 to their Splices. Also look a Fuel Pump Relay Block Pin_1 and Pin_5. Backtrack wires to the same Splices. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 9, 2020 Author Share Posted January 9, 2020 3 minutes ago, Ωhm said: It seems you got a Red wire touching a Yellow wire in the Engine Control Harness. Backtrack wires from D1_5 and D2_4 to their Splices. Also look a Fuel Pump Relay Block Pin_1 and Pin_5. Backtrack wires to the same Splices. Will do this weekend. Thanks Ohm. Will update soon Link to comment Share on other sites More sharing options...
Ωhm Posted January 11, 2020 Share Posted January 11, 2020 If I'm not to late, we need to take the ECU out of the picture before you open up the harness. With battery cables removed, C103 disconnected, disconnect both ECU connectors. Check for continuity between D1_5 and D2_4 again. If continuity still exist, problem should be within the harness, otherwise suspect ECU (internal short). Link to comment Share on other sites More sharing options...
Bob89manche Posted January 12, 2020 Author Share Posted January 12, 2020 5 hours ago, Ωhm said: If I'm not to late, we need to take the ECU out of the picture before you open up the harness. With battery cables removed, C103 disconnected, disconnect both ECU connectors. Check for continuity between D1_5 and D2_4 again. If continuity still exist, problem should be within the harness, otherwise suspect ECU (internal short). I followed these instructions. I also have gone through the wiring harness from relay bank/diagnostic bank up to the MAP sensor checking for any shorts. Going through up to C101 tomorrow. As of now, no change. Found some less than satisfactory connections but all In all, it’s not bad. Not been hacked into by POs at all. Attaching photo of non related connections I found that look like they could go together but seem to be situated too far away from each other. Link to comment Share on other sites More sharing options...
Ωhm Posted January 12, 2020 Share Posted January 12, 2020 One on your thumb is 4W/D switch, on your fingers is Cruise Control ground. Man, I was hoping by now you would have found something. I just know D1_5 (HOT at all times) should not have continuity to D2_4 (SW IGN I1 feed). Not sure about Red or Yellow wires going to C101. Link to comment Share on other sites More sharing options...
Bob89manche Posted January 12, 2020 Author Share Posted January 12, 2020 28 minutes ago, Ωhm said: One on your thumb is 4W/D switch, on your fingers is Cruise Control ground. Man, I was hoping by now you would have found something. I just know D1_5 (HOT at all times) should not have continuity to D2_4 (SW IGN I1 feed). Not sure about Red or Yellow wires going to C101. Thanks. Makes sense as I’m 2WD and no cruise control. Maybe I can just set it on fire and score an insurance payout 😫 Link to comment Share on other sites More sharing options...
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