you could try to check the electric current that is being sent to the light with a volt meter, and comparing it to the other side..... that might tell you if you got electrical problems, if the current checks, then pull out the low beam light " make sure not to touch the accutal bulb " and turn it on, if it glows low, then i donno, but if it glows fine, and glows low when put in the headlight, then your headlights might be bad, but hope for the best