I have a 2011 hs250h, my right headlight marker (the amber one) doesn't illuminate. I've checked the bulb, looks good. Replaced the bulb and checked the harness. It won't turn on... The left side works no problem. Is this a fuse? Is it a bad wire? Or a more sinister issue?

 

Have you looked for corrosion in the bulb socket? That is the most likely issue, after having a new defective bulb.
Does the new bulb work when tested on the other side?

 

Thanks for the reply!

There is no corrosion in the engine compartment, none in the bulb holder and the leads look perfect. I didn't check the other side, it's much less accessible without removing that plastic cover.