95 crown victoria signal light problem

i have a 95 ford crown victoria and it was just wrecked and the entire front cap was replaced my (front) left signal works, but my right signal does not. what could cause this problem? and what can i do to fix it?
There is likely a problem with the wiring. I would suspect that the ground is either not attached or poorly contacting. Look for any loose wires that should be bolted to the body.