Depending on the year model, the headlights are ran on seperate fuses, located in the fuse panel under the hood. You need to get the trouble codes pulled to find out what is wrong. Most autoparts stores do this free. If it is a '96 or newer, one thing to check is the vacuum line going to the EVAP canister behind the bumper, drivers side. I've seen these get soaked with oil and become loose.