Hi my Son has an 07 TL type S that is a fixer upper lol. Every time you turn on the headlights there is a loud short buzz from the passenger side headlight area. Headlights come on but go off soon after but come right back on when you turn the switch on and off. And again the short buzz when doing this. Any idea what this means just trying to narrow it down. My mechanic was not thrilled or eager to mess with it beacause it was electrical sounding. Thanks in advance.

 

igniter/ballast issue

 

Agree it sounds like your ballast/igniter. Just got finished replacing mine a few months ago.

This is one area of the car that can be deceptively dangerous. I had always been taught that a car's 12v dc electrical system is much safer to work on than a home's 120v ac. These ballasts take 12v and increase it to 20,000v. Make sure you or your mechanic take all needed precautions.

 

Why so many mechanics are scared of angry pixies?

If he / you are going to drop the bumper to remove the headlight (required to replace the ballast), one could swap components side to side to figure out what is bad. Although ballasts are usually sold with igniters anyways.
If I would be in your shoes, I would go for used OEM ballast over the aftermarket one. Also, while in there already, might throw some nice fresh bulbs for not much additional labor. I recommend getting Osram CBB.
(unless you replaced bulbs not long ago - they go dimmer over time).