Originally posted by Nightshade
Probably a loose wire in it.
Pull the light out from the door and check the connections and make sure they are tight and rust free. If they are loose just replace the clips on it (easy job 5 minutes max) if that doesn't work then you may have blown the bulb in it and just replace that as well.
The connections are good and the light definitely works cause I've tried it in different sockets like my back door that work good. Could there be something wrong w/ the wiring inside my door?