About two weeks ago I'd had my passenger headlight bulb replaced. It worked for a little bit and then it quit coming on. Now when I turn the lights on it flickers a little bit, but never actually comes on. Could this be a problem with the ballast or faulty wiring? My mechanic said the ballast was a little loose and put some adhesive in to hold it in place, but the problem persists. Any thoughts?

 

Hard to speculate. Could be loose connection, improper install or a faulty bulb.

Pull the fender liner out and check the bulb to see that it's seated correctly. SHouldn't take more than 5 minutes.

If you want to confirm it's the bulbs, swap the bulbs to opposite sides and see if the problem follows the bulbs. if it doesn't, then you have a wiring/ballast issue.