Rear LED lightbar problem

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firemedic723

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I have a 2021 Ram 1500. 2 years ago I installed a OPT7 3-row LED lightbar to the bottom of the tailgate. I purchased the Curt 56584 3-way adapter plug for the 7-pin trailer connection port instead of splicing into the rear tail lights directly. The past few months, at random, my neighbors would text me to say the rear light bar is on while my truck is off. I've also seen it when I lock the truck via the remote, the lightbar will sometimes flash and the bottom row, running lights, will stay on.

On a side note, these are the only electrical extra mods, installed way before LED lightbar, I have done to the vehicle...
1. Replaced headlight, fog light and turn signal halogen bulbs with LEDs (special ones that prevent hyper flash)
2. Installed a LED lightstrip to the truck bed side walls for ambient lighting in the bed (hard wired to battery with in-line fuse and grounded)
3. Installed front and rear dash cam, power via the cigarette fuse from under dash fuse box
4. Installed a blue side-to-side laser light to mimic aftermarket car theft alarm installed (had since 1998 and I love it, haha)

This is what I've done so far to troubleshoot this issue without resolve...
1. When truck is off, at random times, I noticed there is power going to the rear 7-pin plug on the 12volt pin (which is normal) and power to the 10 o'clock pin (NOT normal and tail/running light pin)
2. I replaced the aftermarket Curt 56584 harness with a Hopkins 41153 harness and still the same issue. I verified without any accessory harnesses installed, via voltmeter, power is still going to those same pins.
3. I doubled checked the internal and external fuses, all were OK.
4. OPT7 customer service recommends vehicles after 2019 must have the lightbars hard wired directly ONLY, use of harness adapters won't work. BUT why did it work for 2 years and no all of a sudden not work? Friends of mine have used the Curt harness as well.

So, what's the deal?
1. Is there a faulty trailer connection or brake light relay?
2. Is there an improper ground somewhere?
3. Are the turn signal or running light LED bulbs effecting the lightbar?

To my forum friends.......PLEASE HELP!!!!
 
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Badger 13

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I would take a wild guess and say that the problem is in the lightbar itself. I know a couple of people that have had weird issues with their OPT 7 lightbars. Fortunately theirs were still under warranty and the replacement worked the way it should. I'm sure is not the answer you were looking for, but like you said, it was working for 2 years and then it didn't... Good luck with it.
 

John Jensen

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When you tested and found "power to the 10 o'clock pin (NOT normal and tail/running light pin)", yes, that is not normal. If that's the case the light bar would stay on all the time, but you say it's "sometimes". If it is sometimes the power to that pin has to be appearing intermittently. I don't know what would cause that within the truck. I suggest you disconnect the lightbar and retest the pin. Or temporarily wire another 12v light in place of the lightbar to test whether or not the lightbar is causing the problem. That said, I don't understand how the lightbar could be the problem as doesn't or shouldn't be connected to any 12v hot leads.
 
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firemedic723

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Thank you John and Badger 13 for your responses. Here's the latest update...I omitted the 3-way Curt extension from the rear of the 7-pin connector and plugged the light bar directly into the rear trailer 4-pin connector. Still goes on intermittently. While the truck was off, I popped the hood and found power is going through the 20A fuse (F09, trailer stop, left turn lamp) for the left turn signal causing the light bar to be on. I disconnected the light bar and still have power to the 4 & 7 pin for the left turn signal / tail light pins. I locked and unlocked the truck several times to try and reset or confuse the power distribution. Still have power going to those same pins. Now this leads me to believe something is wrong with the truck. Software issue? Why am I getting intermittent power to the running / left turn tail light via the trailer 4pin/7pin connectors?
 
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firemedic723

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On a side note, the power is only going to the trailer connectors. The front and rear turn signal lights and running lights don't stay on for the truck. Is there wire corrosion somewhere in the wiring going to the rear of the truck into the 4 & 7 pin connectors? Next step is using dielectric spray cleaner into the factory connector from the truck into the backside of the trailer 4/7 connector. Let's see what happens.
 

John Jensen

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On a side note, the power is only going to the trailer connectors. The front and rear turn signal lights and running lights don't stay on for the truck. Is there wire corrosion somewhere in the wiring going to the rear of the truck into the 4 & 7 pin connectors? Next step is using dielectric spray cleaner into the factory connector from the truck into the backside of the trailer 4/7 connector. Let's see what happens.
Hard for me to help further as my 2016 fuse and pin data is different than your 2021.
It seems you've isolated the problem to be somewhere in the harness from the fuse block to the trailer plug. Sounds like a 12v short to the left turn signal/tail light pins. Most likely in the end plug.
 
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