Marker light won't turn off

[MPTee]

I've been a lurker up til now, picking through your knowledgeable postings for tidbits of interest, ending up with a 2022 JLURD about 3 weeks ago from Kent at Peterson's in Idaho. Instantly feel at home in it. This is my 7th Jeep (4 CJ5s, a Jeepster, and a TJ) and without a doubt is the most capable, powerful, mizerly, comfortable rig I've had yet. I'm loving it.
My reservations on buying it had two key points: Would it be too fancy for me (who needs power windows? heated seats? high tech radio?); and is there too much tech reliant on unserviceable tech for a shade tree mechanic to handle? I'm happy to say that I've overcome my reservations on the fancy concerns - i've adapted quickly in the past 2500 miles and can no longer live without these things. But tech? My concern seems valid.

Last night I noticed the side marker light in my RR OEM LED taillight was on without the Jeep running. I've pushed buttons, pulled and seated fuses, removed the taillight completely, disconnected the battery, waited, and finally slept on it. This morning the light is still on.

I was unable to find anything about this on line, here or on other sites. Any ideas short of brining it in for it's first service?

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[pangmaster]

Hi there!

I just saw this, take a look, seems related...
https://www.jlwranglerforums.com/fo...aillight-assembly-wiring-harness-issue.94647/

 

[Reinen]

Hi there!

I just saw this, take a look, seems related...
https://www.jlwranglerforums.com/fo...aillight-assembly-wiring-harness-issue.94647/

Seems like the problem there is the marker light not turning on and the fix is to replace incandescent tail lights with LED. OP has the opposite problem and already has LED tail lights.

I'd take it in for warrantee service. At the very least it will get it on record that you had an electrical oddity. Since it isn't throwing a code, take video/pics of the marker light on and document the exact date & time you shut the jeep off, took the video/pics, etc. This isn't because the dealer is expected to be shady, they just need documented evidence of the issue beyond the cliché "Customer states..." statement to really pursue it. It's also surprisingly common for things like this to stop happening the moment you pull into the dealership for some reason. Murphy's Law.

One possibly stupid question... are you sure the marker light is on? Because I have thought a marker light was on only to find it was an outside light source reflecting inside the lens, making it appear like it was on.

 

[pangmaster]

Seems like the problem there is the marker light not turning on and the fix is to replace incandescent tail lights with LED. OP has the opposite problem and already has LED tail lights.

I don't disagree, it's not exactly the same problem, but when I read something about a wiring harness it seems suspect and worth a look. And maybe a clue when going to the dealer.

 

[GATORB8]

Trying to think of any reason there would be voltage at the tail light with it off.

Anything plugged into the hitch plug?

 

[MPTee]

Good points all. I'll address each to cover as much ground as possible.

Pangmaster - I hadn't seen that recall. Even though the symptoms are opposite of mine, it does make one wonder. I checked my build date and it is 3 days after they ceased having issues, but I will bring it up to the service department. Coincidence? Maybe. But worth considering.

Reinen - Great idea on logging the issues. It'll be next week before I can get to the dealer now, and that's if they see me right away. I'll start a log right away.
And the "reflection" issue possibility isn't stupid - I actually ignored it at least twice before, writing it off as that. It was only last night when I parked differently that I actually confirmed it was on. It does have different intensities - sometimes very subtle, with last night's being the brightest.

GatorB8 - Nothing plugged in at the time, but yesterday was the first time I pulled a trailer. Coincidence? Hmmmm.

Today I disconnected the battery for over an hour (last night was for maybe 10 minutes). Once everything was hooked up again, the light was out. But... after a 300 mile cruise today I just arrived home and saw that the light was on once more.

To the service department I go...
Thanks and have a great weekend all.

 

[mwilk012]

A bad body module or wiring weakly shorted to power is pretty much the only possibility. Try removing the tail light and checking voltage at the beige wire with orange stripe.

 

[MPTee]

mwilk012 - I just tried your idea but couldn't get any reading off any of the wires coming from the Jeep wiring harness. There is a "sub-harness"(?) on the light itself that leads from the input set to the side marker (seen below). I didn't test those leads, thinking that if power is not getting to the assembly it isn't getting to them.
However, what is that tan cylinder in the picture, embossed "Nitto Denko"? Could that be a capacitor that stores power for the LEDs? I'm not an electrical guy, but I do know that I'm not supposed to touch those things even when not hooked up to power (long story, but my memory on the subject is "shockingly" good).
I have noticed that the light is brightest when I initially turn off the Jeep, but slowly dims over many hours (12 hours later it's still visible).

 

[mwilk012]

How were you measuring the input? Did you have a good ground?

 

[MPTee]

Just used a voltmeter. Good on ground - I tested it with the ohm meter first.
I should have tried the voltmeter with the lights on as well - that'd have confirmed my connection. Oops.
My thought on the capacitor doesn't hold water - the light goes out when I unplug the taillight, so the power is coming from beyond the assembly.

 

[GATORB8]

mwilk012 - I just tried your idea but couldn't get any reading off any of the wires coming from the Jeep wiring harness. There is a "sub-harness"(?) on the light itself that leads from the input set to the side marker (seen below). I didn't test those leads, thinking that if power is not getting to the assembly it isn't getting to them.
However, what is that tan cylinder in the picture, embossed "Nitto Denko"? Could that be a capacitor that stores power for the LEDs? I'm not an electrical guy, but I do know that I'm not supposed to touch those things even when not hooked up to power (long story, but my memory on the subject is "shockingly" good).
I have noticed that the light is brightest when I initially turn off the Jeep, but slowly dims over many hours (12 hours later it's still visible).

The tan thing is just a vent.

 

[MPTee]

Just a brief update for those that may be following - I have an appointment at the dealership, but it's about 3 weeks out. I'll let you know what they determine.
Additional symptoms have popped up - When I didn't drive the Jeep one day, the next day it had a dead battery (obvious power drain). When this happened, I got a light saying "Water in fuel". I was over 200 miles into that tank of fuel with no problem, and only 2800 miles on the rig total, so I doubted the idiot light. But, I drained the filter anyway and found NO water.
Also, my "apps" on the radio screen keep changing, deleting themselves randomly, and then reappear as they choose. After I've driven long enough to charge the battery, no more problems.
I'm guessing the light and the apps are additional symptoms of the battery drain.

 

[Dyolfknip74]

Just a brief update for those that may be following - I have an appointment at the dealership, but it's about 3 weeks out. I'll let you know what they determine.
Additional symptoms have popped up - When I didn't drive the Jeep one day, the next day it had a dead battery (obvious power drain). When this happened, I got a light saying "Water in fuel". I was over 200 miles into that tank of fuel with no problem, and only 2800 miles on the rig total, so I doubted the idiot light. But, I drained the filter anyway and found NO water.
Also, my "apps" on the radio screen keep changing, deleting themselves randomly, and then reappear as they choose. After I've driven long enough to charge the battery, no more problems.
I'm guessing the light and the apps are additional symptoms of the battery drain.

This is starting to sound like the shitty batteries. There are a lot of threads with gremlins like this. Also, make sure all your fuses are seated.

 

[MPTee]

Fuses seated (and all checked), and I don't think it's the batteries yet. Once started, they charge up quickly and everything runs fine. It's only after they sat for 36 hours (with the marker light glowing) that I couldn't start it.
Now if I keep this up for the next 3 weeks while waiting for my warranty work, maybe the batteries will go bad from too many charging cycles...

 

[mwilk012]

I’d unplug that marker light if I were you.

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