‘86 MJ rats nest. Please help! No running lights and signal woes

[DzienManche]

So to start off this MJ has been in my family since 86. My grandfather within the past 10 years has had somebody working on it and I think they were cutting corners and potentially losing screws and other components as they reassembled things. He’s had an aftermarket radio put in and I believe a car alarm that is problematic.

 

it doesn’t have functioning running lights, and the turn signals are wonky. So far I’ve upgraded the headlights with sealed LEDs from rock auto, replaced the sockets for the front, turn signals and now replace the sockets for the side indicator lights. The tail lights. I just replaced all of the bulbs.

 

With the key in the on position, the hazards seem to function just fine, the left turn signal seems to function OK, but it does not have the side indicator light, blinking. When I turn the right, turn signal on, the left front side and rear turn signals blink, very dimly, as well as the shifter lightbulb an instrument panel, dimly flash with an alarm sounding until I turn it off. I was on the phone with somebody walking me through a couple of things and I have replaced the hazard fuse, as well as moved the relays around and I replaced one of them.
 

I live in Virginia, so running lights are, as I’m told, required to pass safety inspection. I would like to convert this to my daily driver, but there are quite a few other electrical problems. I need to deal with first. For some reason, the door switches for the foot well lights don’t seem to function, and I’ve tried, jumping the switch and completing the circuit and it’s as if they are not recognizing anything. That’s on both the driver and passenger side, the mechanic told my grandfather to just unplug the lightbulbs if he wants them off. 
 

I used my multimeter to see if I’m getting power to the left side indicator with the left turn signal on, and there is no power whatsoever. With the right turn signal on, it seems to flash, because both wires go to and come from the same spot so I think the mechanic who looked at it before may have screwed with some wiring somewhere, I’m at a loss and I’m very color blind so I can’t trace wires and everything, as somebody traditionally could. I really am to the point where I would pay anyone almost anything to just fix all of my electrical issues because that’s my Achilles’ heel. 
 

I attached the pictures that show me holding both blues and blacks of both side indicator lights, and where they’re tied into. Also, the rats nest of a drivers side wire mess from previous work. I took the dashboard apart for easy access, and so I can take a look, so everything is more exposed, and it typically would be. Please help looking for anything.

[Pete M]

the front corner lights are just marker lights.  they don't blink.   

 

have you run through Cruiser's MJ tips yet?  most are electrical in nature.  the link to it is in the link in my signature. 

[gogmorgo]

For your interior lights, is the dash dimmer turned up all the way? Turn the headlight switch knob, at one end of travel there’s a noticeable detente that turns them on.
 

Turn signals back feeding power through to other circuits is indicative of a bad ground path through a dual-filament bulb. Probably the easiest if not necessarily most efficient way to diagnose is to go around and pull out each turn signal bulb until it quits doing it, and then investigate that particular ground. 

As Pete said, the early MJs didn’t flash the front corner lights, just the lights under the headlights. But good news there’s a diy thread on how to make them alternate flashing with the turn signals. 

While I was looking for that I stumbled across this as well. It would be good to make sure you have the correct bulbs in each socket. Putting a single-filament bulb into a dual-filament socket or vice versa can also cause the back feeding. 

 

When you say the running lights don’t work, are you referring to all the marker/parking lights and also the taillights that should switch on at the same time, or just specifically the front corner lights?

The front corner bulbs are just single filament lights, so if both the wires coming off them are tied together, that’s you’re issue. Wiring them per the above write-up should correct that. 
If you also aren’t getting the front markers (below the headlights) or the taillights to come on when you pull the headlight switch to the first stop, I’d be suspicious of the headlight switch itself and the associated wiring, as it’s a known common problems spot, assuming you have the correct bulbs in all the sockets. The ten-pin connector for the header panel harness (below the driver’s headlight) is also a common issue, as is the connector for the taillight harness (behind driver’s rear wheel) and the ground for the taillight harness behind the driver’s taillight. 

 

Cruiser’s tips at www.cruiser54.com will also be helpful in finding ground issues and just general wiring improvements.

 

Aftermarket installers in general seem to do a good job of messing everything up, but I’ve been in very few Jeeps this old that haven’t had all the wiring in the dash pulled apart and shoved back together in a disastrous tangle. A lot of it was simply velcroed in place and Velcro and associated adhesives fail over time. 

[DzienManche]

1 hour ago, gogmorgo said:

For your interior lights, is the dash dimmer turned up all the way? Turn the headlight switch knob, at one end of travel there’s a noticeable detente that turns them on.
 

Turn signals back feeding power through to other circuits is indicative of a bad ground path through a dual-filament bulb. Probably the easiest if not necessarily most efficient way to diagnose is to go around and pull out each turn signal bulb until it quits doing it, and then investigate that particular ground. 

As Pete said, the early MJs didn’t flash the front corner lights, just the lights under the headlights. But good news there’s a diy thread on how to make them alternate flashing with the turn signals. 

While I was looking for that I stumbled across this as well. It would be good to make sure you have the correct bulbs in each socket. Putting a single-filament bulb into a dual-filament socket or vice versa can also cause the back feeding. 

 

When you say the running lights don’t work, are you referring to all the marker/parking lights and also the taillights that should switch on at the same time, or just specifically the front corner lights?

The front corner bulbs are just single filament lights, so if both the wires coming off them are tied together, that’s you’re issue. Wiring them per the above write-up should correct that. 
If you also aren’t getting the front markers (below the headlights) or the taillights to come on when you pull the headlight switch to the first stop, I’d be suspicious of the headlight switch itself and the associated wiring, as it’s a known common problems spot, assuming you have the correct bulbs in all the sockets. The ten-pin connector for the header panel harness (below the driver’s headlight) is also a common issue, as is the connector for the taillight harness (behind driver’s rear wheel) and the ground for the taillight harness behind the driver’s taillight. 

 

Cruiser’s tips at www.cruiser54.com will also be helpful in finding ground issues and just general wiring improvements.

 

Aftermarket installers in general seem to do a good job of messing everything up, but I’ve been in very few Jeeps this old that haven’t had all the wiring in the dash pulled apart and shoved back together in a disastrous tangle. A lot of it was simply velcroed in place and Velcro and associated adhesives fail over time. 

So the instrument cluster and shifter lightbulbs go on because of what I suspect is a backfeed into the system. Currently I have dual filament lightbulbs in the front driver side and passenger side turn signals, as well as the two lights in the back of each tail light the reverse lighting is the only single filament lightbulb. I have back there. I’ve tried looking for wiring diagrams for the turn signals headlights inside markers, but I can’t find anything that’s easily readable. I was told that the side markers also should blink when the turn signals are engaged, which is why I’ve been looking at that, but in terms of running lights , I don’t have any functionality on any of my exterior lights when I have the switch pulled out to the first position. The headlights obviously will work when I pull them completely out. 

[Pete M]

might be time to pull the headlight switch and check its (and it's harness') condition.   

[DzienManche]

1 hour ago, Pete M said:

might be time to pull the headlight switch and check its (and it's harness') condition.   

Yeah I have everythin torn apart to give it a look. I just need to figure out how to disassemble and pull it

[Pete M]

9 minutes ago, DzienManche said:

Yeah I have everythin torn apart to give it a look. I just need to figure out how to disassemble and pull it

 

you're looking for this little release button (image shows a switch upside down).  that will allow you to pull the handle out.  then unscrew the silver bit remaining at the front with a big flathead screwdriver.   

 

 

[DzienManche]

10 hours ago, Pete M said:

 

you're looking for this little release button (image shows a switch upside down).  that will allow you to pull the handle out.  then unscrew the silver bit remaining at the front with a big flathead screwdriver.   

 

 

I checked the switch and it doesn’t seem to have any visible defects or any issues causing connection problems. It looks almost brand new.

[Pete M]

did you unplug it?  the damage is usually inside the connector.  more importantly, while you're there check for power.   

[gogmorgo]

It does look like there’s been some heat on that connector, but it’s not as bad as most I’ve seen. 
 

If you want, you can probably just get a headlight harness off a junkyard XJ and swap the whole thing. It just unplugs at the 10-pin connector in the engine bay below the driver’s headlight. You might need to pull the header panel to get it out, but that might be easier than repairing the current one if it’s going to be a bunch of work. 
 

 

Here’s a diagram for the headlight switch. Note there’s seperate power sources for headlights and parking lights. You’re looking at the one on the left. You should be able to use a test light pushing into the back of the plugged in connector. 

 

 

[DzienManche]

Did MJs come with keyless entry? Because I think I figured out that the module looks aftermarket and I think may be my issue

[Pete M]

1 minute ago, DzienManche said:

Did MJs come with keyless entry? Because I think I figured out that the module looks aftermarket and I think may be my issue

 

nope.  very few even came with power locks. 

[DzienManche]

Just now, Pete M said:

 

nope.  very few even came with power locks. 

I have power windows and power locks on my 86, those came installed by the factory

[Pete M]

Just now, DzienManche said:

I have power windows and power locks on my 86, those came installed by the factory

 

XLS? 

[DzienManche]

2 minutes ago, Pete M said:

 

XLS? 

Yes. I just didn’t know if those also came with a remote haha

[Pete M]

nice.   top of the line MJs are pretty rare.   

[DzienManche]

3 minutes ago, Pete M said:

nice.   top of the line MJs are pretty rare.   

Thanks. Yeah trying to figure out how I should remove this stupid remote thing because I think it’s install borked my system 

[DzienManche]

I am happy to announce that with the help of my new best friend Steve, the running lights are now functioning, and I believe the turn signal problem is resolved as well. I just need to charge my battery up a bit to give it a full test today. She lives again!

[DzienManche]

Just now, DzienManche said:

I am happy to announce that with the help of my new best friend Steve, the running lights are now functioning, and I believe the turn signal problem is resolved as well. I just need to charge my battery up a bit to give it a full test today. She lives again!

Also, I took that aftermarket BS remote system out and probably salvaged almost $100 in parts! Win-win

[Pete M]

1 hour ago, DzienManche said:

I am happy to announce that with the help of my new best friend Steve, the running lights are now functioning, and I believe the turn signal problem is resolved as well. I just need to charge my battery up a bit to give it a full test today. She lives again!

 

 

[Eagle]

On 10/23/2022 at 10:06 PM, DzienManche said:

 I was told that the side markers also should blink when the turn signals are engaged, which is why I’ve been looking at that, but in terms of running lights , I don’t have any functionality on any of my exterior lights when I have the switch pulled out to the first position. The headlights obviously will work when I pull them completely out. 

 

You were told incorrectly. The side markers do not blink. In fact, in the early days of NAXJA there was a wiring modification posted to make them blink.

 

What are you referring to as "running lights"? Parking lights, or daytime running lights? The MJs did not have daytime running lights in the U.S., only in Canada.

[gogmorgo]

2 hours ago, Eagle said:

 

What are you referring to as "running lights"? Parking lights, or daytime running lights? The MJs did not have daytime running lights in the U.S., only in Canada.

I would assume marker lights. The DRLs are just the headlights at reduced voltage, most people don't notice when they don't work.

[Eagle]

10 hours ago, gogmorgo said:

I would assume marker lights. The DRLs are just the headlights at reduced voltage, most people don't notice when they don't work.

That's probably a fair guess, but in 78 years on the planet and 62 years of driving, I have never heard of parking lights being referred to as "running lights," but there was a Jeep option for daytime running lights, so I thought it better to ask so that everyone can be on the same page.

[DzienManche]

To clarify, it is the lights (whatever you call them) that are turned on with the light control switch pulled out to the first notch. They are now functioning, and the left turn signal is also functioning. When I turn my right turn signal on, the left blink dimmly as well. I haven't narrowed down the issue on that yet, so I search continues.

[gogmorgo]

Those will properly be called the parking lights. The parking lights are made up of various combinations of marker lights, clearance lights, tail lights, etc., depending on the vehicle. No big deal.
 

The left turn signals blinking dimly indicates a ground issue. What’s actually going on is all the parking lights are blinking. One or more of the dual-filament turn signal bulbs on the right side doesn’t have an adequate ground, so it’s finding it via the other filament and the rest of the lights attached to that circuit.