headligh assembly
 

Just bought a used 2002 2500HD 6.0. searched, but was unable to find an answer. What are the clear blinker bulbs inboard of the orange blinkers for and what turns them on/off?

Daytime running lights I'm pretty sure on the 02

If they come on when put in gear, they are daytime running lights.

Is it normal for the main headlights to come on w/ the ignition key?

if its darker yes. you have automatic headlights

and dont cover that little black dome in the middle of your dash under the windsheild...thats your light sensor for your lights