Odd headlight issue

[Aidenmoreno3]

Hey all,

 

I came out to my Jeep tonight to go to the store and realized my headlights running lights, and dash lights won’t turn on. However, the brake lights, turn signals, and some lights all work.

 

I recently swapped out my dashboard for one less…. Ruined, and am thinking I missed something. The only things I unplugged were what absolutely needed to be, that being the ac controls, cluster, headlight switch, and so on. 
 

When I first turned the car on after the swap I noticed the headlights were flickering and acting funny but they ended up staying on. Now that they’re not working at all I took the old headlight switch off the old dashboard and swapped them out to no avail. 
 

the odd thing is when I go to turn the headlights on the open door buzzer goes off almost like it’s letting me know a fuse or relay was tripped. 
 

any ideas? I’m so frustrated I’m just done for the night and going to sleep

[eaglescout526]

This would be a great time to add the relay harness upgrade. 
 

Have you checked your fuses?

[Aidenmoreno3]

19 minutes ago, eaglescout526 said:

This would be a great time to add the relay harness upgrade. 
 

Have you checked your fuses?

I checked the fuses under the dash on the firewall and the fuses under the hood. Nothing blown. I’ve been looking into that upgrade but I wanna know what’s causing the issue first you know? Is it possible that the old switch is also bad and I should buy a brand new one? It worked fine before the dashboard replacement 

[eaglescout526]

Have you cleaned your grounds?

[schardein]

What year?

If both your headlights and parking lights are affected, those are separate fuses, seems unlikely that is the case.

Do any of the front lights work?  If no, you might check the front light wiring harness connector that is near the airbox (driver side fender).  It's common for those terminals to turn green with corrosion and also completely corrode away.

That doesn't explain no dash lights though.

The headlight switch has a ground wire that attaches to a tab on the switch body.  Did you make sure that is connected?

Did you look at the headlight switch connector?  It may be melted or have burnt terminals.

The buzzing sound- are you sure it is the warning buzzer?  Do you have the headlight sentinel system?  It is a silver box that is mounted to the steel dash frame just to the driver side of the steering column.  I have heard mine make noise under certain circumstances.  I've never known one to go bad, or what affect a bad one would have on the system, but perhaps if you do have it, just unplug it and see if that changes anything.  Vehicles that don't have the option simply don't have the relay, but the plug is present in all MJs.

[Aidenmoreno3]

2 hours ago, schardein said:

What year?

If both your headlights and parking lights are affected, those are separate fuses, seems unlikely that is the case.

Do any of the front lights work?  If no, you might check the front light wiring harness connector that is near the airbox (driver side fender).  It's common for those terminals to turn green with corrosion and also completely corrode away.

That doesn't explain no dash lights though.

The headlight switch has a ground wire that attaches to a tab on the switch body.  Did you make sure that is connected?

Did you look at the headlight switch connector?  It may be melted or have burnt terminals.

The buzzing sound- are you sure it is the warning buzzer?  Do you have the headlight sentinel system?  It is a silver box that is mounted to the steel dash frame just to the driver side of the steering column.  I have heard mine make noise under certain circumstances.  I've never known one to go bad, or what affect a bad one would have on the system, but perhaps if you do have it, just unplug it and see if that changes anything.  Vehicles that don't have the option simply don't have the relay, but the plug is present in all MJs.

So it’s a 1992 and I’ve seen the plug you’re talking about, I don’t believe I have the relay.

 

none of the front lights work (EX: headlights, high beams, running lights) but the blinkers do. 
 

I have made sure that the ground to the replacement switch is contacting and not corroded. 

 

I will double check the connector to make sure that it’s not burnt and destroyed. But the switch is basically brand new making me think the previous owner had this same issue at some point.

 

The buzzing: that’s what’s confusing me. It’s the same noise when you open the door when the cars on or turn the dome lights on via the headlight switch (I know the switch isint the issue since that part works so it’s getting power). Unless maybe like half the switch is bad? But it seems unlikely since both switches have the same issue 

 

 

[Aidenmoreno3]

4 hours ago, eaglescout526 said:

Have you cleaned your grounds?

Which grounds are you referring to?

[eaglescout526]

All

[Aidenmoreno3]

3 hours ago, eaglescout526 said:

All

Theres a lot of grounds in the car I’m not sure where I’d even start. But just thinking out loud if it wasn’t grounded wouldn’t the whole switch not work? 
 

I get where you’re coming from but saying clean all the grounds is like saying make sure it’s plugged in. I’m looking for answers as to where specific grounds pertaining to the headlights would be or where a relay is I don’t know about. 

[gogmorgo]

The headlight ground goes through that 10-pin connector.

Diagram credit to Cruiser54.com. Use pin positions, wire colours tended to change year to year so they're not 100% reliable.

I'm uncertain where it goes from there, but I'm certain it exists somewhere on the internet if you google it.

 

It makes a lot of sense that this could be a ground issue. The turn signals working can be explained by the fact a dual-filament bulb will ground through the opposite filament's circuit when the bulb is missing the proper ground.

But using that pinout and a test light will tell you whether it's a ground problem or a power delivery problem. You can connect the clamp on the test light to the positive battery terminal to check a ground.

Lighting circuits are very basic electrical diagnosis. You need power to the bulb and you need ground coming away from the bulb. Somewhere the path is broken. Start at the component that's not working, figure out which side is not working, then trace the fault back up the circuit until you have it pinpointed.

When two electrical components fail at the same time the most likely culprit is where the circuits come together.

There are wiring diagrams in the Master Thread in the DIY and tech writeup forum. While the Renix diagrams aren't fully accurate for a '91+, the lighting circuits are mostly the same. Again look for connector pin locations rather than wire colours because the wire colours aren't fully reliable.

[schardein]

Which buzzer do you have, the black one or the blue one?  It is located right next to the fuse box, driver side of fuse box.

 

You might try this:  Pull the driver side headlight bezel.  Then you can remove the driver side headlight.  Unplug the headlight switch connector.  Check that you have power at the connector for the headlights first (terminal B1)(volts check setting).  It should be hot all the time, so you don't need the key on.  If you do, then using a electrical meter, check for continuity (continuity or resistance setting) from the headlight power wire (terminal H) to the headlight bulb connector.  If you don't have continuity, then you will have to dig deeper.  It could be the high/low beam switch, the firewall junction block, or the front lighting harness connection near the air cleaner box, or the wiring anywhere along that circuit.  I would also check for a short to ground the same way, put one probe in the headlight switch connector, the terminal sending power to the headlights, and touch the other probe to ground.  It should not have continuity.  Tracking down issues like this can be tedious and time consuming but that is your only course.  You may have to get longer leads for you meter, or improvise an extension.

 

I've included some pictures to help with what each wire does on the headlight switch.  First pic is the headlight switch with each terminal marked with a letter.  Second pic is a pinout of the headlight switch connector.  Last is a little diagram I made describing what each wire does.

 

Also, check your grounds.  I think there are grounds that bolt down on the front lighting harness?  I'll have to research that one.  But one simple check, the headlight bulb connector has three wires, high beam power, low beam power, and ground.  Determine which one is ground and check continuity from there to the negative battery terminal. If no continuity, start tracing that wire from the connector.

[Aidenmoreno3]

****UPDATE ****

 

Hey all,

 

whelp after 2 days of being pissed off at my truck, buying a new switch, and learning how a multimeter works, it was a 40a fuse under the hood causing the headlights not to work:/
 

I tested the continuity of the headlights, the plugs, the headlight switch, and nothing was adding up. I just started pulling fuses even though I had already checked all of them in the car. I probably sanded around 10 grounds in the engine bay and in the cab under the dash. 
 

I'm trying to remember what the fuse panel said it was for to help someone in the future but I can’t right now. Thanks to everyone who helped me out, turns out I’m just a tard and it was an easy fix. I did learn a lot and will be doing the relay harness setup that Jeep cables provides:

 

https://www.jeepcables.com/products/daylight-headlight-harness?gad_source=1&gclid=Cj0KCQiAn-2tBhDVARIsAGmStVmMnVqntW1QI3bVfNnR7hCWztzEak1FZ6tcwAqGwv51ff4XTkZ9LP4aAvjfEALw_wcB

 

I know it’s more expensive than some other options but I’ll buy once cry once. I have the Jeep cables battery terminal upgrade already so I know their stuffs reliable 

[Aidenmoreno3]

1 hour ago, schardein said:

Which buzzer do you have, the black one or the blue one?  It is located right next to the fuse box, driver side of fuse box.

 

You might try this:  Pull the driver side headlight bezel.  Then you can remove the driver side headlight.  Unplug the headlight switch connector.  Check that you have power at the connector for the headlights first (terminal B1)(volts check setting).  It should be hot all the time, so you don't need the key on.  If you do, then using a electrical meter, check for continuity (continuity or resistance setting) from the headlight power wire (terminal H) to the headlight bulb connector.  If you don't have continuity, then you will have to dig deeper.  It could be the high/low beam switch, the firewall junction block, or the front lighting harness connection near the air cleaner box, or the wiring anywhere along that circuit.  I would also check for a short to ground the same way, put one probe in the headlight switch connector, the terminal sending power to the headlights, and touch the other probe to ground.  It should not have continuity.  Tracking down issues like this can be tedious and time consuming but that is your only course.  You may have to get longer leads for you meter, or improvise an extension.

 

I've included some pictures to help with what each wire does on the headlight switch.  First pic is the headlight switch with each terminal marked with a letter.  Second pic is a pinout of the headlight switch connector.  Last is a little diagram I made describing what each wire does.

 

Also, check your grounds.  I think there are grounds that bolt down on the front lighting harness?  I'll have to research that one.  But one simple check, the headlight bulb connector has three wires, high beam power, low beam power, and ground.  Determine which one is ground and check continuity from there to the negative battery terminal. If no continuity, start tracing that wire from the connector.

 

Hey thanks for the reply! Wish I had gotten on and seen it sooner. I ended up doing this anyway and confirmed it was getting power using the continuity setting on my multimeter. I appreciate the help

[cruiser54]

Now put a harness in.  https://cruiser54.com/?p=115