I'm guessing the amperage draw, albeit low, is enough to fool the truck into thinking you have a trailer hooked up with lights pulling power through the plug.
I also used my trailer back-up wire but only as a trigger.
I have a relay with the main juice coming from the battery up front, not through the reverse wire for the trailer. Its used only as a signal to turn on the relay.

This is the only thing I can think of that could be causing the random issue.
If your actual reverse bulbs inside the tail light are also LED I would tap into that wire as the amp draw from all 4 LED's would be okay for that wire and it for sure wouldn't indicate to the truck you have a trailer plugged in.
It may be random just based on amperage draw and heat. Sometimes it tells the truck you have trailer based on the amperage draw and sometimes it doesn't. Heat from the LED's increasing with use does change their efficiency and amperage draw.
Just some thoughts

 

I'm not picking on anyone in particular here, to the contrary, I appreciate the info. I'd like to add that nobody has mentioned the trailer bulbs. They have to be added to the equation. It may be a good idea to change the trailer bulbs to LEDs too.
TomJV

 

Copy thanks. I am guessing its a draw issue of some sort. I will move the wires and tap them into each individual reverse light.

 

looks great

 

I wired mine into the reverse wire on my trailer plug no relay wirks great

 

Flush mount also. I measured about 56 times before actually cutting lol

 

That looks absolutely fantastic - I had to go outside and take a look at my dash to look at that portion - your install is so clean, it looks like it came that way from the factory. Do you have a link to where you found that switch panel?

I'd like to be able to turn my reverse lamps (in the tail light assembly) on without having to put the key in and shift it into reverse with the engine off, and that switch panel looks superb.

 

Another shout out to this tip. After putting these in the reverse lamps, factory lens assembly, I bought more to put in the cargo lights for the bed.

Holy cow. Even with the spray-in black Rhino Lining, it's bright as day in that truck bed.

Here's a couple pictures, one shows all four from the back, and the other shows just the reverse lights lighting up the front of my house, my Suburban, and the side of the neighbor's house. These are truly fantastic lights, I'm sure the other (more drastic) mods that have been shown in this thread are brighter, but for the time being, these are such an improvement over the stock, I think I'll stick with them for a while.

Already have one neighbor whom is not all that Internet-active wanting me to order him some for his Chevy...

 

Thanks a ton for the compliments. I like them but give most of the credit to the switch mfg.
I ordered the switches from OTRATTW (Over The Road And Through The Woods) Strange name I know but they have some of the coolest switches Ive found.
https://otrattw.net/home.php

 

Thanks for the link... Going to have to place an order with them in the very near future.