I had my headlights off my 02 to replace those little white clips that like to break. I noticed that in addition to the main headlight bulb is a small bulb that looks like a turn signal light.

What is this for? I cant see any reason for it. Anybody know the part number? I have been looking on rock auto and they dont show anything.

 

It's some sort of marker type light which comes on, I believe, when the parking lights are on.

 

It's to light up the headlamp and make you more visible while parking lights are on, without blinding or annoying others and also your regular night bulbs will last longer. I use the parking lights in low visibility situations for the same reason most cars today have Daytime Running Lights. It's a #194 bulb i believe.

 

I use Sylvania 194 ZEVO LED's & they last much longer & WJSJ9 described them perfectly.

 

 

They come on with low beams too. I rewired mine to run as my DRL since I have LED main beams now. The reduced voltage of the DRL won't fire the ballast, hence the switch

 

Also know as city lights!

 

Saturnine has it right; I've seen them referred to as city lights. I've seen many vehicles zipping around London with them on after dark. The streets are generally well lit enough that drivers don't need headlamps to see where they're going, but the city lights help others see them. I wish they were common in cities here; sure beats having brighter lights blinding you. I often turn mine in on in daylight as daylight running lamps. The tail lights come on too, of course.