Forgive me if this info is buried somewhere on these forums. I couldn't find it.

I've been trying to piece info together to add low-beam HIDs to my 2002. Confounding issues include the variable definition of OBS vs NBS, and the broken link to Sylvania's site. So here goes, courtesy of ippielb at gmtruckclub.com

Low Beam Headlight Bulb Size: 9006
High Beam Headlamp Light Bulb Size: 9005
Parking Light Bulb Size: 3157A
Front Turn Signal Light Bulb Size: 3157A
Rear Turn Signal Light Bulb Size: 1157 or 3157LL
Tail Light Bulb Size: 1157 or 3157LL
Stop Light Bulb Size: 1157 or 3157LL
High Mount Stop Light Bulb Size: 921
Fog/Driving Light Bulb Size: 880
License Plate Light Bulb Size: 194 or 67/97
Back Up Light Bulb Size: 1156 or 1156 or 3156
Front Side Marker Light Bulb Size: 3157A
Rear Sidemarker Light Bulb Size: PC195
Ash Tray Light Bulb Size: 194
Glove Box Light Bulb Size: 194
Map Light Bulb Size: 168 or 211-2
Dome Light Bulb Size: 211-2
Step/Courtesy Light Bulb Size: 1003 or 211-2 or 74
Trunk/Cargo Area Light Bulb Size: 912
Under Hood Light Bulb Size: 89 or 93
Instrument-General Light Bulb Size: 161 or 194 or 74
Check Engine Indicator Light Bulb Size: 74
Hi-Beam Indicator Light Bulb Size: 74
Seat Belt Indicator Light Bulb Size: 74
Brake Warning Light Bulb Size: 74
Automatic Transmission Indicator Light Bulb Size: 161
Directional Signal Indicator Light Bulb Size: 74
Daytime Running Light Bulb Size: 4114LL

This obviously has several INTERIOR lights, but since I am interested in the headlights, I posted it in the EXTERIOR forum.