70barracuda Posted October 30, 2019 Share Posted October 30, 2019 Pretty much as the title says, after months of absolutely no problems my headlight switch decided it wanted to get hot tonight. I preemptively installed the harness while rebuilding the whole jeep pretty much and never had an issue. Then all of sudden tonight the switch got so hot the pull knob melted off. I ordered a new switch and supposedly a harness plug that will work. Anyone have this happen? Just a bum old switch or possible short somewhere? Link to comment Share on other sites More sharing options...
Pete M Posted October 30, 2019 Share Posted October 30, 2019 ouch! well, at least you stopped it before anything caught fire. a short is always a possibility. what else flows through the switch? dash lights? Link to comment Share on other sites More sharing options...
70barracuda Posted October 30, 2019 Author Share Posted October 30, 2019 It was damn close. Smoke was pouring out the defroster vent. the harness should have taken the main current of the headlights off it. After I caught it the b pillar lights wouldnt turn off so I pulled the fuse. Marker lights and dash lights go through too. Everything still works fine, no blown bulbs or fuses blown either. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted October 30, 2019 Share Posted October 30, 2019 melting the plug used to be blamed on the draw from the headlights, solution would be a headlight harness kit to take the main load off the factory harness. With led lights available I don’t know if these old assumptions are true. I do know on the Jeeps I put a cheap headlight harness connecting them to the battery for the main power draw the headlight switches seemed to stay cool. The 1984-91 headlight switch plug are different from 92 up, there is a 92 up plug with harness pigtail available What I had to do was compare the 92 up plug to the older one and cut off the piece that wasn’t needed for the 84-91 switch. If your dash harness is newer this may not matter. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted October 30, 2019 Share Posted October 30, 2019 I would pull all the lights that run off that switch and carefully examine the sockets and perhaps the bulbs themselves. Sounds like a short Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 30, 2019 Share Posted October 30, 2019 were your headlamps coming on and off while this was occurring, is there any melted wires anywhere else any damage anywhere but the plug and switch? Link to comment Share on other sites More sharing options...
70barracuda Posted October 30, 2019 Author Share Posted October 30, 2019 Headlights stayed on no problem. I only noticed it because of the smoke. They actually still work fine. Haven't gotten a chance to rip it all apart yet. Link to comment Share on other sites More sharing options...
54bobby Posted October 30, 2019 Share Posted October 30, 2019 7 hours ago, Warren Mohler said: were your headlamps coming on and off while this was occurring, is there any melted wires anywhere else any damage anywhere but the plug and switch? sorry to thread jack but, i recently backed my boat trailer lights under salt water while launching. after i pulled out, the right rear trailer light was full of water. about a half mile or so up the road, headlights started doing the on then off thing with no set pattern to it. haven't gotten around to it yet but could salt water into the trailer short out the lamps and cause this intermittent problem? Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 30, 2019 Share Posted October 30, 2019 10 minutes ago, 54bobby said: sorry to thread jack but, i recently backed my boat trailer lights under salt water while launching. after i pulled out, the right rear trailer light was full of water. about a half mile or so up the road, headlights started doing the on then off thing with no set pattern to it. haven't gotten around to it yet but could salt water into the trailer short out the lamps and cause this intermittent problem? Well...water and electronics don’t mix. Water conducts electricity so it’s possible the water is making contact with the ground and power of the socket. Does the problem persist if the trailer is unplugged? Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 30, 2019 Share Posted October 30, 2019 5 hours ago, 70barracuda said: Headlights stayed on no problem. I only noticed it because of the smoke. They actually still work fine. Haven't gotten a chance to rip it all apart yet. chances are this problem started long before you installed the "by pass" harness, the switch is designed to handle the load of the lamps, the wires are sized to handle it as well, I believe when you do tear into it you will find damage to be only switch and plug. Damage will likely be to one terminal far greater than others around it. A short on headlamp circuit should have the internal breaker to open and close causing lamps to go off and on and continue to do that while lamps are on. a short on park lamp circuit should have caused blown fuse. look around real good while replacing switch and plug. which I would recommend sounds like it got REALLY HOT. if no damage is found in harness just inches away that is all that should be needed and problem was in connection, keep us posted with what you find Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 30, 2019 Share Posted October 30, 2019 41 minutes ago, 54bobby said: sorry to thread jack but, i recently backed my boat trailer lights under salt water while launching. after i pulled out, the right rear trailer light was full of water. about a half mile or so up the road, headlights started doing the on then off thing with no set pattern to it. haven't gotten around to it yet but could salt water into the trailer short out the lamps and cause this intermittent problem? not if the truck side is wired properly, boat trailer wiring is pretty simple many times people will use regular trailer or automotive lamps on a boat trailer this is a no no. marine lamps are either water proof or designed to drain as soon as trailer is pulled from water either way you should always unplug trailer and allow bulbs to cool before backing in. the only thing to stay powered would be brake lock out solenoid if you have hydraulic surge brakes on trailer Link to comment Share on other sites More sharing options...
70barracuda Posted November 1, 2019 Author Share Posted November 1, 2019 So the only spot that was melted on the switch was the orange and black wire. Haven't found a full diagram but it seems like it's the dash dimmer wire. Mine did flicker on and off when I tried to adjust it from the very beginning but I switched to led so I couldn't use it anyway. The switch was very clearly melted. Link to comment Share on other sites More sharing options...
JMO413 Posted November 1, 2019 Share Posted November 1, 2019 1 hour ago, 70barracuda said: So the only spot that was melted on the switch was the orange and black wire. Haven't found a full diagram but it seems like it's the dash dimmer wire. Mine did flicker on and off when I tried to adjust it from the very beginning but I switched to led so I couldn't use it anyway. The switch was very clearly melted. mj1988electricalmanual_(1).pdf This is the 88 electrical manual PDF. Link to comment Share on other sites More sharing options...
70barracuda Posted November 1, 2019 Author Share Posted November 1, 2019 2 hours ago, JMO413 said: mj1988electricalmanual_(1).pdf 8.04 MB · 2 downloads This is the 88 electrical manual PDF. Thanks! Link to comment Share on other sites More sharing options...
70barracuda Posted November 1, 2019 Author Share Posted November 1, 2019 So the only melted parts were the actual switch and the part of the connector that had the dash lights wire in it. I traced as much as I could and no wire was burnt at all throughout the dash. I spliced in the new harness and plugged the switch in. Tested it before putting it all back together and the switch stayed ice Cold with all lights on for 15 minutes. I guess I'll chock it up to a faulty switch? Link to comment Share on other sites More sharing options...
Ωhm Posted November 1, 2019 Share Posted November 1, 2019 Sounds like you nailed it, faulty switch. Link to comment Share on other sites More sharing options...
JMO413 Posted November 1, 2019 Share Posted November 1, 2019 33 minutes ago, 70barracuda said: Thanks! Welcome. Hope that will help. If I remember right the organization l orange and black is for the interior lights. Link to comment Share on other sites More sharing options...
1989commanche Posted November 2, 2019 Share Posted November 2, 2019 On my Comanche there are a few orange and black sets of wires with plugs for instrumental lights for things that are not there like the fog lights cargo lights etc. there are at least 3 separate plugs dangling under there without bulbs in them two sets had just the wires dangling with no connectors just two cut wires when I tested them with a test light they were live when the dash lights were on. I taped up the ends so they wouldn’t short out while bouncing around out in the hills. You may want to take a look under the dash area. Link to comment Share on other sites More sharing options...
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