03 silverado tail lights
#4
The only thing you need the harness for is the turn signal lights there is the main turn signal light then there is 194 bulb in the lower corner that alternates between the main ts bulb and the small one otherwise it wont light up or work. Not a big deal and not worth the price of the harness IMO.
#5
Yes they will fit. Like mentioned above...you don't really need the harness (for example if you bought them used), but if you buy them over the parts counter (or for example somewhere like GMPartsDirect) the harness is included. All you have to do is unscrew the old light and unplug the old harness. It screws up and plugs in perfectly! Hope this helped


