CEThomas Posted July 12, 2007 Share Posted July 12, 2007 Head light problem. If I pull the head light and test the socket I get 12.5V at the low and high side. plug in the head light and then get nothing. no light and no voltage :nuts: Where is the light relay? and anything else I need to check on?? Also If I pull the flash to pass the head lights work and yes both bulbs are good. Charles Link to comment Share on other sites More sharing options...
Wildman Posted July 12, 2007 Share Posted July 12, 2007 Al shucks.......and I was going to ask if the bulbs were any good, Man, you took all the fun out of that. The head light relay should be in the Power Distribution Center. I'm thinking this, you got a '88 steering column, with a '88 smart switch, and I'm thinking that the flash to pass is also the high beams, you said when you pull the switch, you have flash to pass, but that should lock on for the high beams too. So, you have the flash to pass, but no head light, low or high beam, and we talked about this, did you change out the head light switch?? When you tested the sockets, did you ground the meter on the body, or at the ground in the socket. I ask this cause you might not have the socket grounded. Man......I know as much about your MJ as you do, and your 300 miles away ;) Link to comment Share on other sites More sharing options...
Oizarod115 Posted July 12, 2007 Share Posted July 12, 2007 those pull switches can go bad. my brothers fried itself Link to comment Share on other sites More sharing options...
CEThomas Posted July 12, 2007 Author Share Posted July 12, 2007 I replaced the dimer switch with one out of a 92. Unless a resistor for the headlights is built into the switch, it looks to be OK. I have 12.5v at the bulb socket grounding at the socket on high & low. As soon as I plug in the bulb the voltage drops to 0v just like I have a bad short somewhere. I even took the front light harness and bulbs from the XJ and pluged into the MJ and get the same thing. Also parking/turn lights work fine :nuts: I also have been able to do this from the dimer switch. Jumper from pass to flash power lead to the high / low light wires and the lights will work. Jumper from the main power lead to the high / low light wires and no lights. And I have power to the main lead until I jump it to one of the light wires and then it drops to 0v. I know this has to be a simple fix but I am at a loss :nuts: Link to comment Share on other sites More sharing options...
Wildman Posted July 12, 2007 Share Posted July 12, 2007 It's sounds like when you install the bulbs, it's back feeding thru the bulb and killing the power, that would put you back to the source, the dimmer, or smart switch. Your closing the loop with the bulb. Using both the MJ and XJ harness's and bulbs would tell you that. The harness and bulbs are both good, back to the source. There has to be a problem with one of the switches, or change out the relay and see if the relay is bad, struck in the "closed" position. You had said that cleaning the smart switch solved a couple other problems, correct? There could be a pinched wire some place that could be causing your problem too. Lots of parts moving around. Link to comment Share on other sites More sharing options...
CEThomas Posted July 12, 2007 Author Share Posted July 12, 2007 Where is the relay located for the lights? I do not see anything listed in the top cover of the Power Distribution Center. The other location for relays I found is is under the dash and that box has 3 relays. a red one pluged into a red socket, a black one that is pluged into a tan socket and a small black on that is pluged into a yellow socket. Think I can rule out the smart switch as I do not see and fuction on the head lights but to push the rod down to the dimmer switch. When I tested the plug at the dimmer switch was with it unpluged from the switch and I get the same problem. It has to be in the ground / relay / or switch " but that would be my last choice". Link to comment Share on other sites More sharing options...
Wildman Posted July 12, 2007 Share Posted July 12, 2007 Your right I forgot that there is just a rod that hits the dimmer switch on the bottom of the column. I'll see if I can find which relay is for the headlights, and where. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 12, 2007 Share Posted July 12, 2007 Head light problem. If I pull the head light and test the socket I get 12.5V at the low and high side. plug in the head light and then get nothing. no light and no voltage :nuts: Where is the light relay? and anything else I need to check on?? Also If I pull the flash to pass the head lights work and yes both bulbs are good. Charles There are no relays for the headlamp circuit, only for the factory foglamps. Since the "flash-to-pass" works on the column stalk, the harness is most likely okay. I think your headlight switch is fried. Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 I found it and yes it has a relay in the system. It's a large silver box under the dash between the collum and fuse box. The MJ did not have it and the dash / harness we got for it did not have it. Was looking at the XJ tonight and followed the wire from the dimer switch to the relay. pulled the relay and found the plug in the MJ and pluged it in and all works well now :D One more thing down now :cheers: Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 13, 2007 Share Posted July 13, 2007 I found it and yes it has a relay in the system. It's a large silver box under the dash between the collum and fuse box. The MJ did not have it and the dash / harness we got for it did not have it. Was looking at the XJ tonight and followed the wire from the dimer switch to the relay. pulled the relay and found the plug in the MJ and pluged it in and all works well now :D One more thing down now :cheers: Great, glad you found it. What you are describing sounds like the headlamp delay module. It's a relay of sorts, but more like a timer, not for protection. Just curious, do you have the delay function now? Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 Did not check that, but the XJ did not have it and our ZJ that has it has a switch that you can turn the delay on and off. The plug has 2 black ground wires, the brown / black wire going to dimmer switch, a pink/red wire, and 2 other wires that I do not rember the color. If it's the delay then is there a jumper that plugs into it? Link to comment Share on other sites More sharing options...
rockhardzj Posted July 13, 2007 Share Posted July 13, 2007 Sort of on topic, but off. How much rigging will it take to use my current 88 headlights and marker lights with the 98 XJ harness? Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 13, 2007 Share Posted July 13, 2007 The wire count is right, but the colors are not, according to my FSM. The headlamp delay module has an 8-pin connector, only 4 are used. Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 Sort of on topic, but off.How much rigging will it take to use my current 88 headlights and marker lights with the 98 XJ harness? To much :wall: Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 The wire count is right, but the colors are not, according to my FSM. The headlamp delay module has an 8-pin connector, only 4 are used. Got the Factory Schematic and it's the delay module. Looking like I may have a grounding problem and the module is acting as the ground now:nuts: Looks like I may have to pull the dash if I can not locate to problem soon :cry: Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 13, 2007 Share Posted July 13, 2007 The wire count is right, but the colors are not, according to my FSM. The headlamp delay module has an 8-pin connector, only 4 are used. Got the Factory Schematic and it's the delay module. Looking like I may have a grounding problem and the module is acting as the ground now:nuts: Looks like I may have to pull the dash if I can not locate to problem soon :cry: You can take the delay module out of the circuit by disconnecting (and insulating) the TAN 12AWG wire input to the delay module at pin 6. This at least will tell you if the problem is in the delay module. Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 If I unplug the delay and take a jumper from the tan/black wire to which ever wire in the plug that is hot when you pull the switch on ( looked at so many color wires today I do not recall what color it was now) everything works as it should. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 13, 2007 Share Posted July 13, 2007 If I unplug the delay and take a jumper from the tan/black wire to which ever wire in the plug that is hot when you pull the switch on ( looked at so many color wires today I do not recall what color it was now) everything works as it should. Yes, that's effectively what you did. You jumpered the output of the dimmer switch directly to the headlamp switch, bypassing the delay module. Glad you got 'er done. Link to comment Share on other sites More sharing options...
CEThomas Posted July 13, 2007 Author Share Posted July 13, 2007 So if I just direct wire it it will be OK? Not like a MJ needs a delay :D Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 13, 2007 Share Posted July 13, 2007 So if I just direct wire it it will be OK? Not like a MJ needs a delay :D If you just wire pin C from the dimmer directly to pin H of the headlamp switch, it should work fine. Mine does. But the delay module also feeds the security system (if you have one) so you will prolly lose some functionality there. Try it and see if you do. Also, did you try just pulling the Headlamp Delay fuse (25A, #11) in the fuse block? Link to comment Share on other sites More sharing options...
CEThomas Posted July 14, 2007 Author Share Posted July 14, 2007 No did not pull the fuse, did not even know it had a fuse to pull ;) but who needs a security system on a MJ :D Link to comment Share on other sites More sharing options...
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