ARareBreed Posted June 5, 2017 Share Posted June 5, 2017 I'm literally at on the last straw with this issue. I'm getting flickering front and rear parking lights as well as transfer case bulb, gauge bulbs and cigarette lighter bulb. The ground behind the tail light looks to be clean and clear. Fuse #15 is good. I already got a new headlamp switch think it was that. Still flickering. The weird thing is if I leave the lights on in parking light mode that over time they flicker less. Any ideas? Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 5, 2017 Share Posted June 5, 2017 Did the headlight switch harness and plug look good? Not melted? Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
a bum with money Posted June 5, 2017 Share Posted June 5, 2017 Did you check the 8 or 10 pin connecter behind the left front headlight? It's in the engine compartment. Sometimes the pins get corroded and/or gunked up. I think its the main part of the lights and stuff. It's worth a look. Bryce Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 I unplugged the headlight harness below the radiator cap and the remaining bulbs still flickered. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 5, 2017 Share Posted June 5, 2017 It seems like it would be a ground problem or a melted/melting headlight switch plug. When mine tried to melt down it did all kinds of weird things. Unless it's a renix 87-88-89? (I can't see signatures with the details in this app) maybe it's the c101 connector issue. Other than this, I'm not sure if bad bulbs/sockets can cause flickering. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 It's not a renix. The front parking lamps and instrument lights stop flickering when I unplug any of the 3 connectors for the tail light harness. 1. Connector near spare tire 2. Connector behind drivers seat 3. Connector behind parking brake lever It's got to be a connection at the tail lights,right? Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 5, 2017 Share Posted June 5, 2017 Oh, what does the tail light harness look like? Each side should have a separate harness that clips/plugs in the main body harness. I'm explaining it badly, right and left tail light bulb sockets should be on a harness that plugs in to the main body harness. At least that's how it is for XJ I assume MJ had something similar. If it does I'd try disconnecting each side one at a time and see what happens, and/or inspect the wires from the last point to the Taillights to see if there is a bad wire. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
cruiser54 Posted June 5, 2017 Share Posted June 5, 2017 The ground "looked" good behind the taillight? Did you remove it and scrape paint off under it? This may help also: http://cruiser54.com/?p=249 Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 5, 2017 Share Posted June 5, 2017 This may be what the MJ tail light harness looks like, Different from the xj but I'd bet the problem is some where in there. Either a bad ground at a socket or a bad wire somewhere Swamp rat @ the commence club had this post from 2013 about the MJ tail light wiring http://comancheclub.com/topic/40102-tail-light-wiring-diagram/ HO tail light wiring: Black - ground Brown/Green - back up lights Blue/Red - running lights (parking) pink (salmon) - brake & right turn signal Green - brake & left turn signal Renix taillight wiring: Brown: Right turn and brake light Black: Ground Blue: Tail (parking) lights Brown with white tracer: Backup light Grey with black tracer: Left turn and brake light so renix to HO plug convertion would go as such: Black - black Brown/Green - brown/white Blue/Red - blue Pink - brown Green - grey/black Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Eagle Posted June 5, 2017 Share Posted June 5, 2017 My guess is the headlight switch itself. Try jiggling the knob gently and see if that results in flickering of the lights. Link to comment Share on other sites More sharing options...
cruiser54 Posted June 5, 2017 Share Posted June 5, 2017 My guess is the headlight switch itself. Try jiggling the knob gently and see if that results in flickering of the lights. excellent idea. This may help also and certainly won't hurt. http://cruiser54.com/?p=110 Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 5, 2017 Share Posted June 5, 2017 X2 on the headlamp switch and/or connector. Pull it out and check it. Are you possibly running H4 headlamps or any other auxiliary lights w/o relays through the headlamp switch? Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 I replaced the headlamp switch to no avail. I disconnected the plug under the radiator cap going to the front headlight harness as a process of elimination attempt. The rear harness and gauges still flickered. But once I unplugged any of the 3 plugs I mentioned above, the gauges and fronts stopped flickering. Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 This may be what the MJ tail light harness looks like, Different from the xj but I'd bet the problem is some where in there. Either a bad ground at a socket or a bad wire somewhere Swamp rat @ the commence club had this post from 2013 about the MJ tail light wiring http://comancheclub.com/topic/40102-tail-light-wiring-diagram/ HO tail light wiring: Black - ground Brown/Green - back up lights Blue/Red - running lights (parking) pink (salmon) - brake & right turn signal Green - brake & left turn signal Renix taillight wiring: Brown: Right turn and brake light Black: Ground Blue: Tail (parking) lights Brown with white tracer: Backup light Grey with black tracer: Left turn and brake light so renix to HO plug convertion would go as such: Black - black Brown/Green - brown/white Blue/Red - blue Pink - brown Green - grey/black Sent from my iPhone using Tapatalk Pro I'm honestly thinking a bad ground at a socket in the rear. That will be my next attempt. One concern that it might not fix the issue is this: will a single bad socket in a tail light effect the entire parking lamp/instrument light circuit? Other wise I will be out of ideas without actually pulling the harness apart one wire at a time. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 5, 2017 Share Posted June 5, 2017 Do fix the ground behind the left tail lamp first. I did mine like the below - an 8AWG wire tied to a bumper bole. If no help - Fuse F15 (Park/Tail Lamp) on your 91 interior fuse block is fed by 40A PDC fuse F12 (Head Lamp Dist). Make sure that fuse is correct. Pull it, clean the contacts, then reinsert to see if that helps. If not, then it's time to start pulling bulbs one by one......... Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 Do fix the ground behind the left tail lamp first. I did mine like the below - an 8AWG wire tied to a bumper bole. If no help - Fuse F15 (Park/Tail Lamp) on your 91 interior fuse block is fed by 40A PDC fuse F12 (Head Lamp Dist). Make sure that fuse is correct. Pull it, clean the contacts, then reinsert to see if that helps. If not, then it's time to start pulling bulbs one by one......... I'll try all those fixes. thanks. You can confirm one bad bulb will cause entire circuit failure? Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 5, 2017 Share Posted June 5, 2017 I'll try all those fixes. thanks. You can confirm one bad bulb will cause entire circuit failure? Not the bulb, but a bad socket. If you have a socket that's causing a partial ground loop, that can cause the symptoms you are seeing. When you pull the bulb it usually opens the socket ground loop and changes the symptoms. And while you're doing that you might as well clean out all the dried out grease/crud that you'll find on the socket bases. Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 I'll try all those fixes. thanks. You can confirm one bad bulb will cause entire circuit failure? Not the bulb, but a bad socket. If you have a socket that's causing a partial ground loop, that can cause the symptoms you are seeing. When you pull the bulb it usually opens the socket ground loop and changes the symptoms. And while you're doing that you might as well clean out all the dried out grease/crud that you'll find on the socket bases. I did that a few months ago. I cleaned out all the old yellow grease from the factory and put in a bunch of ox-gard. Maybe that could be my issue. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 5, 2017 Share Posted June 5, 2017 Yeah, that stuff is conductive and could bridge the bulb pins. Not too likely though. I usually just thinly coat the bulb's brass base, not the contacts. Link to comment Share on other sites More sharing options...
ARareBreed Posted June 5, 2017 Author Share Posted June 5, 2017 After tearing down the truck into pieces to find the issue, the problem has been solved. Too much oxgard conductive grease in the rear passenger lower tail light socket. Learned a lot through this whole fiasco. Now I can begin putting the truck back together.... Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 5, 2017 Share Posted June 5, 2017 Well, it's good you found it. So the symptoms went away when you pulled the bulb? Link to comment Share on other sites More sharing options...
ARareBreed Posted June 6, 2017 Author Share Posted June 6, 2017 Yeah, it was a mixture of a bad bulb and too much grease. I never would have thought a single bad socket would cause issues through the whole circuit. Link to comment Share on other sites More sharing options...
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