I looked and haven't found any threads specific to this issue, but I apologize if there is one and I missed it.. I have a 2004 TL with 175,000 miles on it. Other than having to replace the oft mentioned O ring on the power steering pump, no real issues. EXCEPT- over the last 6-8 months the headlights won't come on when turned on, or one comes on then not the other, vice versa. It seems to occur on the driver side more often, but also occurs on the passenger side, sometimes neither headlight comes on and I am left with the fog lights. I have checked the fuses all are fine, the relay box seems to be fine. If the bulb(s) were shot I don't think they would light up at all, yes? Any and all assistance is appreciated.

 

Could it be the ballast?

 

Not sure on the ballasts...? If so, is there a way to quickly (and safely) check them? My question would be 1) would they work off and on as they do--when they are on there is no discoloration or delay or anything and 2) what are the chances that it would happen on BOTH sides??? My experience with eletrical systems would lead me to think that it is wiring or grounded related of some sort, but I'm noooooo expert (which is why I'm on this forum looking for advice from some.. I'm working with stock OEM lights and everything, no mods or tweaks from me...thanks

 

hmm..................