Bed Cargo lights won’t fully shut off / flicker

[FXDBRP]

I recently noticed that the cargo lights in my late 2021 trucks bed will never completely “turn off”. They very dimly flicker almost as if some residual or phantom power is trickling into the LED cargo lights. It happens constantly even after the truck has been locked and the key has not been nearby for hours. The lights will momentarily get slightly brighter if the drivers or passenger door handles are touched maybe waking up the modules. The top mount 3rd brake light is also not affected and all the other lights are still fully operational and function as normal otherwise shutting off completely. I connected the truck to Forscan and I have a DTC code for B153E Trailer Hitch Light Output and if I run a self test on the BCM I also get a B14D8 Bed Lamp Output code. I’ve noticed no issues with trailer lights connected so I am not sure what is causing this. I thought it might be a bad switch so I also removed the switch in the bed but that seems to only send a signal to the BCM and so the lights still flicker even with the switch disconnected. Anyone else run into something like this or is this normal?

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[Ford blue blood]

LEDs require a good ground. Tired or mildly corroded grounds will give you "magic" twinkles with LEDs.

 

[Porpoise Hork]

Could also be the button causing issues. Try disconnecting the harness to it to see if it shuts off. It's a cheap part and easy to replace at about $30.

FL3Z-9C888-B

 

[FXDBRP]

LEDs require a good ground. Tired or mildly corroded grounds will give you "magic" twinkles with LEDs.

Thanks for the reply. Any idea where to locate the ground for the lights?

 

[FXDBRP]

Could also be the button causing issues. Try disconnecting the harness to it to see if it shuts off. It's a cheap part and easy to replace at about $30.

FL3Z-9C888-B

I disconnected the button and it made no difference at all. It seems that the button just sends a momentary signal to the body control module to turn the lights on and doesn't actually operate as an on/off switch cutting power to the lights.

 

[Porpoise Hork]

Well that's poopy.

 

[FXDBRP]

Update if anyone else experiences something similar: took the truck to the shop and from what I was told they went over all the traces and ground connections relating to the box lights. While nothing stood out to be loose or corroded it seems just reseating/tightening the connections has fixed the problem. I haven’t noticed any flickering since.

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