These are the years and models that have this dome light:
FITS:
1988-1991 LIGHT DUTY C TRUCK CONV CAB 4X2
1992-1996 LIGHT DUTY C TRUCK CONV CAB 4X2
1997-2002 LIGHT DUTY G VAN FULL SIZE
1988-1991 LIGHT DUTY K TRUCK CONV CAB 4X4
1992-1996 LIGHT DUTY K TRUCK CONV CAB 4X4
1992-2002 MEDIUM DUTY KODIAK - TOPKICK
2003-2004 MEDIUM DUTY MODEL C4500/C5500
I did not use the existing wiring because I wanted the lights to come on when I opened the door, so I ran wires above the headliner to the driver's side dome light. I had some 3-lead wire, so I ran that to ground, door switch power, and 12v constant. The door switch power is hooked to the center light and the maplights through diodes so that all 3 lights come on when the door is opened. The diodes prevent reverse electrical flow, though, so when I hit the maplight switch, only that maplight comes on. The lights are very brights, but I had to make a custom center light with parts from radioshack because the ebay auction didn't come with all of the parts. For $5, though, I'm not complaining.