2001 Ford explorer sport trac headlight problem?

[C B]

i had a wreck on right side and had to get all new front cap every light is new on front except left headlight i'm talking assembly and all except for the left headlight. since i got it out of the shop i have noticed the new right headlight is not as bright as the old left i changed bulbs on both to have same lights on both sides but still same result could someone give me an idea why the right is not as bright thanks