Issues with Passenger Side Marker Signal Light

futhgar

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Joined
Mar 20, 2024
Messages
30
Location
Clearwater, FL
Hello everyone!

I apologize for the long post but I wanted to describe it as best as possible. We've been working on fixing / upgrading things on our TJ and in the process of replacing the side marker light assembly and bulbs we ran into an issue that we're having a hard time figuring out, could use some help!

What we changed for the lighting:
- We replaced the bulbs with stock versions, both front turn signal bulbs and side marker signal bulbs.
- We replaced the sockets for the turn signal lights for Dorman 645657 Turn Signal Lamp Sockets. The stock ones had broken plastic on the edges where it grabs the assembly.

Conditions:
The dashboard displays a constant Right Turn Signal symbol when the lights are turned on.

  • Scenario #1: When headlights are turned on, the headlights and two front signal lights will engage and turn on. The Driver side side marker light engages as well but the Passenger side marker light turns on with a light dim.

  • Scenario #2: With the headlights turned on, when the turn signal is put to the right position (passenger side), the passenger side front turn signal will stay on constant and not blink, while the side marker light will blink but dimmed out.

  • Scenario #3: With the headlights turned on, when the turn signal is put to the left position (driver side), the driver side turn signal will blink correctly as well as the side marker light will blink correctly.

  • Scenario #4: With the headlights on, when the hazard lights are engaged, the driver side front turn signal and the side marker lights will both blink correctly. The passenger side front turn signal will not turn on or blink but the side marker light will blink at full luminosity.

We checked the ground cables and they are all connected on both sides. We did see that the previous owner had spliced into the wiring to connect the fog lights but the sockets are disconnected currently, and he also cut off the wiring to these two boxes that are screwed to both sides of the Jeep side fenders:

1713486872550.jpeg


1713486910598.jpeg
 
IF you are comfortable using a Volt Ohm meter; I would start by testing the voltages going to both side markers to compare voltages when there is power going to the light bulb sockets.
The boxes that are mounted to the inside of the fenders are what remains of the previously installed lighting (possibly aftermarket headlights) and can be removed.
What is the orange wire for with the abandoned connector attached ? Probably the remains of the previously installed wiring.
I would trace the wiring for both side markers and compare connections to see if the previous owner damaged the wiring or has any creative connections remaining.
 
IF you are comfortable using a Volt Ohm meter; I would start by testing the voltages going to both side markers to compare voltages when there is power going to the light bulb sockets.
The boxes that are mounted to the inside of the fenders are what remains of the previously installed lighting (possibly aftermarket headlights) and can be removed.
What is the orange wire for with the abandoned connector attached ? Probably the remains of the previously installed wiring.
I would trace the wiring for both side markers and compare connections to see if the previous owner damaged the wiring or has any creative connections remaining.

Thank you!

Those are going to two fog lights the PO had installed - I had them disconnected since the wiring was poorly done. I'm planning to replace them eventually.

I should have a meter around, I'll test each pin on the sockets for each marker via pin + ground. I'll write back in the results.
 
IF you are comfortable using a Volt Ohm meter; I would start by testing the voltages going to both side markers to compare voltages when there is power going to the light bulb sockets.
The boxes that are mounted to the inside of the fenders are what remains of the previously installed lighting (possibly aftermarket headlights) and can be removed.
What is the orange wire for with the abandoned connector attached ? Probably the remains of the previously installed wiring.
I would trace the wiring for both side markers and compare connections to see if the previous owner damaged the wiring or has any creative connections remaining.

Alright - So I went to the wiring with a voltmeter and tested for continuity at first.

For the front facing signal lights:

If I turn on the headlights I will get continuity in the black wire, but no continuity on the black/yellow or the white/red wires.
If I turn off the headlights I will get continuity in the black wire and the black/yellow but not continuity on the white/red wire.

While blinking, the voltage will switch between 9Vish to 12Vish..

1713654509310.jpeg


For the side marker lights:

If I turn on the headlights I will get no continuity in the black wire or white/red wire.
If I turn off the headlights I will get continuity in the black wire but not continuity on the white/red wire.

Voltage's here went as low as close to zero and up to 3 Volts.


1713654637756.jpeg



Things that I did while troubleshooting:

  1. There are two wires coming off the harness where it splits to the side marker, front signal and fog lights. Those wires were supposed to be attached to the frame as ground and I noticed that if I touched them, the headlights would shine brighter. One of the wires was lose so I soldered them together with a new pigtail and repositioned the ground. Now the headlights both have the same luminosity.
  2. You were right about the aftermarket lights. I traced it and looked like all of that wiring had been removed but the boxes were left behind. I went ahead and removed all that, including a cancelled ground wire that was going to the frame. Did this on both sides of the grill.
 
Attached is the headlight wiring for your year TJ to assist you in troubleshooting.
There is another page 8W-50-3 from the Factory Service Manual that can be downloaded from the TJ Resources section on this forum.

Headlight Wiring.jpg
 
Last edited:
Thank you
Attached is the headlight wiring for your year TJ to assist you in troubleshooting.
There is another page 8W-50-3 from the Factory Service Manual that can be downloaded from the TJ Resources section on this forum.

View attachment 520335

Thank you! I went ahead and got the diagrams and checked where in the circuit I am having problems.

I took a step back to measure the voltage again. With the headlights on, I took a voltage reading on the side marker signal light and I see that I'm getting 11v at the side marker signal bulb socket. Would it be fair to say I may have some corrosion or poor wiring at that splice 142 or 144 where the black wire connects to the front turn signal?

1713726452402.png
 
I would certainly check the connections at Splices 142 and 144, but I would also check the terminals 1&2 in the turn signal lamp and Splice 118 since power from the headlamp switch is fed thru S118. Also check Splice 125 which is where the ground connects to G103 (main ground for the side marker and turn signal lamps).
 
I would certainly check the connections at Splices 142 and 144, but I would also check the terminals 1&2 in the turn signal lamp and Splice 118 since power from the headlamp switch is fed thru S118. Also check Splice 125 which is where the ground connects to G103 (main ground for the side marker and turn signal lamps).

So - looks like we had a bad socket after all. Replaced and everything is working fine now!

Next thing will be figuring out why the fog lights won't work. We have the realy, Jeep is prewired, we have the MFS but we get no indicator on the dashboard, no fog lights. Should be fun...
 
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