Light problems on 03 trailblazer

On my 03 trailblazer the passenger headlight (low beam) stopped working. I bought a new bulb for it. Went to put it in and when i unplugged it one side of the plug was black and burnt. The bulb was not blowed. What would cause this to happen?These pictures are of the plug when i unplugged it. I do not see any reason for this to have happend. The wires look good and there is nothin shorting out that i can see. Any help would be appreciated.

Had the same thing on my 2002 when using Silstar bulbs, Napa makes a heavy duty replacement plug, this can happen from bad conections or bad ground in that circuit. I left the covers off the back of lamps for better cooling also.

Had the same thing on my 2002 when using Silstar bulbs, Napa makes a heavy duty replacement plug, this can happen from bad conections or bad ground in that circuit. I left the covers off the back of lamps for better cooling also.
Thanks alot. I will go by Napa Monday and get me a plug. I will leave the cover off also to get better cooling. That makes sense. Thanks. I took the light out and the inside of the lens is clean as can be but the outside is covered with somthing. I have cleaned it with several things, I recently tried mothers and the turtle wax one with the sanding pads. It helped some but not much. Any suggestions you might have.Thanks again

Once they are pitted or severely damaged from sand or uv rays, you will never get them really cleaned up.