2000 K3500 LS, extended cab
The light bar at the top center of the cab.
It both a cargo light and third brake light.
Old one burnt out.
Can't find a replacement for it.
Tried one from amazon, but to short an narrow.
Any ideas???

 

My memory might be wrong but didn't those lights have replaceable bulbs? If you need to buy one look at the link.

https://www.carparts.com/search?q=th..._light&vehicle[cylinders]=8&vehicle[liter]=6%2E5&vehicle[submodel]=LS&vehicle[model]=K3500&vehicle[make]=Chevrolet&vehicle[year]=2000

 

The bezel has corrosion, so some of the circuit has rotted.
It's a sealed unit. Can't get the the wire.

 

I have a 1996 C1500 and a 2006 Silverado, and neither have a sealed 3rd brake light / cargo light assembly.

The old body style has 2 screws that are used to take the lens off, exposing the fixture itself, which has 4 socketed bulbs. Those bulbs are a pain to pull out without rubber gloves. The socket assembly screws to the cab with screws exposed after removing the 2 that hold the lens on.

On the new body style, the 2 screws secure the entire assembly to the cab, and it pulls out on its wiring harness. The board that holds the bulbs does pull out, as seen in this video: