2003 Express 3500

Clearance lights In-Op and would like to sort out what's wrong.
I'd appreciate if I could get wire color codes, and I believe there's an upfitter wire for clearance lights.

No idea how this guy got away from the DOT deadlining the thing. yikes.

Thanks in advance.

 

gmupfitter.com

 

Thanks!
I looked at this link of yours in another thread. I didn't see wiring diagram for upfitter clearance.
Very possible I'm not looking in the correct place

 

2003 information is sparse. You'll have to look at electrical manuals for the newer models.
The wiring on these vans hasn't changed a great deal.