Dome light flickering on door mode

My dome light always seems to flicker or dim on DOOR mode when the truck is off and I'm exiting the vehicle.

It's done it for awhile but seems to have become slightly worse. It's pretty bright and stays solid in ON mode.

Any idea what could be causing it?

 

Is it stock or LED?
Some LED's cause the body ECU to not properly control the dome circuit.

 

It's stock. Probably the original. I've never changed it since I've owned the truck. Seems to be plenty bright and work just fine when I flick the switch to ON

 

When the switch is in the Door position the Body ECU controls the ground for the dome light on the blue wire so you likely either have a wiring problem or a failing Body ECU, have you ever had any water intrusion in the cab that you know of?

 

Poor ground through the door courtesy switch plunger.

 

Quick test, try the other door.
See if the light still has issues.

The chances 2 switches are bad are slim.
But possible.

 

What is a body ecu, is that what controls the lights and electronics in the cab? I have had probablems with water leaking in through the rear glass but I got it sealed up about 5 years ago and haven't had a problem since.

 

I also tried the passenger door, same effect. Random dimming/flickering

 

Yes it is integrated with the interior fuse box, you may unplug the connectors and look for burnt pins, corrosion, or evidence of water intrusion.

 

Where would I look for the interior fuse box? I though there was only one on my truck under the hood.

 

It's behind the compartment door to the left of the steering column.

 

Thanks. I'll see if I can pull that fuse and check it

 

Back side of interior fuse box with the Body ECU Cover removed.

 

Occam's razor......After messing around with the fuses for a bit and not finding any issues, I found out it's the little sliding switch on the light itself.

When it's slid as far as it will go to the DOOR side, is when I experience problems. If I move it just a little bit to the OFF position, almost halfway between DOOR and OFF it stays bright the whole time the door is open. No issue. OFF position works like normal. However, if I move it too far to the ON position, like as far as it will go, it goes off.

It's like something in the switch itself is just slightly out of alignment. The entire dome light housing is kinda flimsy and moves around alot maybe that has something to do with it. Honestly, now that I know its quirks and can stop then flickering/dimming effect, I'm not too worried about it. I would still like to see if I can't fix it if I'm able to find the time soon.