anyone? instead of changing the whole set of fog lights can I just change the light bulbs in it? thank you.
I can't really tell what you're after here. What is "white" light to you? And what is meant by "LED headlights?" There are no LEDs in the headlights. The "fog lights" are just ornamental.
Yes you can change the bulbs. If you want them to better match the HID's then try Sylvania Silverstars/SilverstarUltra's in the 9006 flavor. If too pricey for you then search ebay for some cheapo's. 9006 is the size. 4300k to 5000k kelvin is what you need to look for. Anything above and it's going to look blue/purple. Here's a little help to changing the bulbs 2004 Prius Light Upgrades Happy modding! EDIT: If you want an HID kit it is possible, but I don't recommend it. The fog assemblies are not made for HID. Several people here have done it and they love it.
Silverstars are white. Had a pair as headlights. They do have a short life if you leave them on all the time. some have used HID kits. They should be fine since the foglights are mounted quite low so glare isn't an issue.
I think the color temp for SilverStar Ultra is near 4100K. So compare to the factory HID's 4300K the SS Ultra maybe close (still not HID w/ some yellowish), but it all depends on how close you really want to match.
I put silverstars in my foglights. The lights look whiter from the outside. From the inside, I see very little diff. I changed all the head light and foglights to silverstars on my wife's Outback, and the difference was noticable, no so to me in the Prius. If you have an extes $50, go for it. Remove the lower access panel - it takes about 1/2 hour. There is a link in the mods section...where this post should be.