So this subject has been covered but I just wanted to get a quick answer rather than spending a ton of time on it.
The other day I found one of my bed cargo lights out, I got a replacement from NAPA and plugged it in and next thing I know the brake lights, 3rd brake light, cargo lights, trailer brake controller light, and ABS light are permanently on when driving the truck. When I shut the truck off they stay on too; well except for the CEL ABS light obviously. So I googled this and found the culprit could be something to do with the trailer brake circuit. I unplugged the feed power to it where it was connected to a fuse with an auxiliary tab in the fuse panel. All lights went out and all seems good now. I will say that I still had the speedometer and no other symptoms. Could anyone briefly touch upon why/where/how this happened? Or if it's easier link me a thread or threads that could directly pertain? Thanks fellas.

PS. I recently bought a boat and have been towing quite a bit, boat trailer is rigged with all led lights; thought this might be noteworthy.

 

Bueller....Bueller......Bueller?

 

This is a BUMP for you. I noticed you havent had a "quick answer"

 

Appreciate that!

 

So by "cargo lights", you mean the white lights in the cab roof that go on when you open the door, along with the dome/courtesy lights? Well, those are in the same housing as the center stop light. I'd look for a wire crossed between those two circuits, up there. Pull the housing off and check the wiring on all three sockets as far up as you can reach. Maybe try removing those replacement bulbs you installed and see if the problem goes away, since that's when the problem started happening.

 

Thanks, I already inspected the wires, and unplugged the bulb I put in; no difference. The only thing that made a difference was as I stated, unplugging the trailer brake controller. This rectified the condition. This problem is a known quantity, I was just hoping someone could verify the symptoms/cause. My truck is fine now.