Tail light relay
 

Does anyone know what this thing is? It looks like a relay, with 4 connectors, but I'm not so sure. Two of the pins take 12vdc to them, and the others have continuity to the ground on the tail lights. Its located under an access panel, next to the kick panel on the rear drivers side (see photo). This is out of a '97 Elantra, so its dusty, and a bit rusty.