i just noticed my drivers side side marker light(both bulbs) are not working, ive already checked the bulbs they were fine i even replaced with new ones just to see, but still nothing. i went to check the fuse but from what i can tell there is no specific fuse just for the sidemarkers. I did notice around the connectors(on the outside of them, not where the bulb connects) that there is some dirt build up is it possible that there some dirt/grease over time and has gotten between the bulb socket and the connectors or is it more likely a short? and if it is a short can i fix that myself, im selling the car and want to fix it before the buyer takes it, preferable without having to take it to the dealer

any advice is appreciated