I have an 03 and it has the extra bulb and I know it's an 03 because I'm the first owner of it. You all so have to make the bulb connector holes bigger on the back of the lights I've help friends out with this and no you don't need the extra wire! Good luck man

 

If it is a gmc you need to modify the socket plugs to fit into the silvy lights, as they are different. From what I have seen the 03 lights also have the extra bulb.

 

I made the clip holes bigger so it don't miss up the plugs

 

You can get lights and harness from ebay for $60. That's what I bought.

 

I see some guys that it is a direct swap (ignoring the extra bulb that isn't required) & others saying to modify clips & socket plugs & such.

 

If you take your taillights out and put them next to a silverados taillight you will see the clip holes are bigger on the gmc side just take a razor blade and make them bigger not my first time!!!

 

Yeah. Nothing is beyond making it fit. I stuffed 315s on 11" wide/7" backspacing wheels under my 1987 GTA. Original size was a 245 on a 16" wheel. Just had to move a "little" sheetmetal out of the way. Just wanted to see if I could find out what I'm in for ahead of time.

What are these "clip holes"? I am new to the 99+ trucks so it is all a new game for me with new terms for lots of stuff.

 

The ones on my truck in the pics I just put on a Sierra two weeks ago and now have LEDs taillights now.

 

The clip hole are for snapping the lights in place if you try to put the connectors/clips in u will see witch ones need to be cut!

 

Well **** guess you learn something new everyday.