Anyone know where I can find these. I see them on some 2500s and sierra c3's. They are those three red lights that are right under the tailgate, and i think that they are LEDs but not sure.

Rear Clearance Light (http://www.gmdieseltech.com/store2/cart.php?target=product&action=view&product_id=16215&category_id=254)

thanks, that is what i was looking for

I bought mine at Tractor SUpply company for about $12. I spliced them into the parking light wire on the right rear tail-light. (I didnt want to splice near the trailer connector, since that gets hit with road water.)

the website said that Duallies are required to have the lights. Anyone know why?

Its a DOT requirement is do to their width. Same reason why the quad-steers have corner marker lights and roof lights, the trucks are wider.

(I think....)

Its a DOT requirement is do to their width. Same reason why the quad-steers have corner marker lights and roof lights, the trucks are wider.

(I think....)

That is exactly correct - IIRC, the limit is anything wider than 80" must have them.

thanks for answer. Makes sense.