It is most probably the headlight switch. It is a cheap part. They may have it at your local auto supply. To remove: Remove the dash bezzel, remove the lower dash cover, remove the ac duct behind dash cover. This will get you access to the wiring harness and clips. Locate the clips and detach. It is a tight fit. Pull fast and hard on the switch knob to remove it from the switch assembly, then proceed to remove and replace with a new the switch. 30 minute job.