LED Trailer Lights Stay on When Disconnecting from Tow Vehicle

Question:

My trailer lights wont all shut off even when unplug from the truck. Its a 19 LED light but 3 or 4 of the LEDs stay on even when my trailer is unplugged from the truck. What would cause this?

asked by: Krystina K

Expert Reply:

Generally you see this situation on a vehicle that has LED lights because there is a power bleed coming from a different circuit into the lighting circuit. LED lights require a lot less power than incandescents, that's one of the biggest benefits of them. So even a very small amount power can be all they need to light up.

Your situation is a little different since your trailer's lights should have absolutely no power supplied to them once you disconnect the truck. But since the lights are obviously drawing power from somewhere you most likely have a power bleed coming from a breakaway battery or trailer battery. You might test this by disconnecting any batteries on the trailer when LED lights are still on after you've unplugged from your truck to see if they go out.

An issue like this is a weak ground on the power source or a short somewhere in the circuit. Make sure the ground locations are clean and free of corrosion. Including the mounting studs if the lights are grounded through the studs. Also inspect all of the trailer wiring for any can of damage or pinch points.

If you're still having an issue after this let me know, and we'll do more troubleshooting to find a solution.

expert reply by: Charles S

Stu

2/23/2024

Brand new 5th wheel (2024) forest river Sandpiper when i arrived to use found the fuse for refrigerator blown. Company put 10amp in instead of required 20amp. Installed new fuse found another 10 amp blown replaced it. Now parking lights are on. I am plug in to park power

Jerred H.

2/24/2024

@Stu Since your trailer is brand new, I recommend you stop messing with the breakers and any other electrical components and contact the dealer you purchased it from and follow their recommendations. This sounds like it could be a bad ground or faulty wiring. You don't want to mess something up that would void your warranty because you are dealing with something that came defective.

Kevin B.

10/23/2024

Haha I had the same exact issue after reading this alarm bells just started dinging. I was like oh the ground. I had wired everything directly to the junction box and I forgot to make a ground directly to the trailer so when I was plugging the seven pen in it was giving the trailer a ground, but when I unplugged it, there was no ground so that’s why the lights still had charge