Mopar wiring harness to flat tow 2020JLUR behind RV only works for about 15 min

Terminex

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Matt
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Omaha
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2019 JLUS
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Fixing stupid....
If i remember correctly Pull out the fuse, and then use a tiny flat head screwdriver. (Jewlers or eyeglass repair size screwdriver)

there is a “tab” that is holding the ends in place.
 

JeepN3RD

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Sammy
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1946 Willys CJ2a, 2019 JLU Sport S
Ok I am trying to figure this out, I think nearly identical situation. My Mopar harness works just great when attached to my 2015 Dodge Durango but when I hook it to the RV I am getting nothing is what I am remembering. I do remember hooking up just a 7 pin tester on RV and I can see turn signals and such on that little LED but that does not tell me if I have enough juice to run tail lights?

Trying to not get this out of order but I think what I did next was find this message / thread and ran just a single wire up to my battery in my motorhome (starting battery...) and then I would get a a very weak signal (basically dim lights is all) when hooked into the RV. But nothing flashing etc. I could hear some "electrical sounds" when I touched the wire to the RV battery and like I said I would now get a dim light but nothing else.

Next I bought a set of LED towing lights that you just hook to 4 pin flatwire on RV. (7 pin to 4 pin adapter on RV) and got nothing... except very dim once again with the 12v/power wire ran to the RV battery. Was running out of time and energy and gave up but really want to figure this out.

I am an electrical newb.. I think you mentioned running a 12v wire to the 7 pin... what was the other end, did you just run to your battery or other 12v source? I am assuming my battery is 12 even though they are huge / diesel pusher 8D battery?!

Any thoughts are welcomed folks! I am thinking next of maybe getting an all new 7 pin harness and wiring it from scratch to my RV? RV is 1999, so has old school tail lights / and resulting voltage? How much voltage does it take to correctly work for a 2021 "bulb" in the JL?

(Keep it simple for me like old school bulb / wiring on your RV tail lights probably takes 4 watts but your JL needs 10 watts or something...and you need to...) so again..I know accounting not electric!
 
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