foglight lowbeam doesn't come on, but highbeam does..
 

Alright I replaced the original halogens with Silvanias and they've been working fine until like maybe a month ago where my passenger side headlight stopped working and appeared to be burned out. But for some reason it only does not work when the foglight is on the lowbeam setting. When I turn on the highbeams, it comes one for some reason so I know that the bulb is not burned out. Do you guys have any idea why this might be?

The H4 is a dual bulb, so it is possible that the fog light burned out but the high beam did not. How long did you have the Sylvanias in? If you use the fog lights on all the time they can burn out pretty quickly.

Yeah, there are 2 filaments, 1 for high beam 1 for low beam, so one could burn out and the other can still work.

oh ok I had no idea that there were two filaments in the bulb...then it makes perfect sense. I guess we learn something everyday. They've only been in for like 4 months but went out at the end of three...the strange part is that i don't really use them that often and it i guess it burned out. But thanks for the info.

Yeah the aftermarket H4's burn out pretty quick. When I had the Silverstars though they lasted more then 3 months. More like 10 months. Did you touch the bulb with your bare hand? The oil from your fingers can cause them to burn out sooner.

hmm maybe i could've without realizing but i'm pretty sure i didn't cuz i was really careful and it came with a big sticker taht said that i should too lol but I guess I'm gunna have to change them. Anything off the top of your head on which ones i should get that pretty much looks the same but lasts longer? What u said was tru about the H4s, on slyvania's website, they say the silverstars have the shortest life span...too bad mine was 3 months hah

I've had my Piaas in for nearly a year now and they are still working fine. You'll have to do some research to find out which color you ar most happy with though. I use the H4 Super Xtreme model #15760. I think that they are very close to the stock HID color and am very happy with them.

I also use the Xtreme white wedge bulb #19172 for the markers and clear corners just in case anyone was wondering. They also match pretty well.

Right now I have the PIAA Xtreme White. They are still a bit yellow though, but close to HID color. I have actually been looking into the H4 market and the different brands and color temps. If you want I will email you the spreadsheet I am working on. Email me at skeletoncru@sbcglobal.net if you are interested.