I tried replacing the factory headlight bulbs in my 99 with higher intensity ones, and the driver side headlight doesn't come on unless I use the high beam, it doesn't work on low. Anyone familiar with this??

 

bulb prolly crapped out already, even if you just installed it...i've had it happen before...switch back to stock headlight bulbs and see if those work, if they do, the bulbs crapped out....

 

Remove the offending bulb from the headlamp housing. Look closely at the filaments inside the bulb. I bet your low-beam filament is burned out. Bummer. (If you're not sure what you're looking for, & you have your OEM bulbs handy, compare the look of the filaments in the two bulbs side-by-side).

Contact the company u bought them from - see if they'll do anything for you. Odds are they won't, but you never know until you ask.

 

I've pretty sure it's not the bulb. Originally, I used a set that I had on my 3rd gen, and I thought it crapped out. This time, I bought a brand new set, and it's doing the exact same thing. Is there something that's regulating the power to the headlights?

 

In addition to checking the filaments, have a look at the wiring harness on the malfunctioning light. Check for melted wire insulation or damaged wires. If you're using overwattage bulbs, you may have fried the wiring.

 

I just used one bulb from the old set, and one from the new....ones I felt were "good ones" and now it works fine. all the bulbs look fine, I don't understand.

 

Electrical problems can be so. . .

Sounds like whatever the problem is, it's intermittent, which usually points to a bad electrical connector or a short. Since it's the lowbeam on one side that's giving you the problem, you should check for continuity (multimeter or test-light) along the wire leading to the low-beam. Trace backwards from the base of the bulb harness, determining which wire is "hot" (+) when the lowbeams are on. Check that circuit as far back as you can, until you find the source of the problem:

-maybe a chafed wire, or bad connection somewhere. . .

There is of course the distinct possibility that the bulb you first installed has an invisible defect, and that this has nothing to do with your wiring at all.

Here's a test: By my account, you now have 4 9004 bulbs in your possession (old set + new set). If you can plug 3 of the 4 bulbs into the harness base & make each of them light up in succession, odds are, you've got a defective bulb.

Best of luck.

 

Thanks for all the input, peeps. The bulbs worked fine when one is the higher intensity, and the other one was stock...just to show it worked. I then switched the order of which head light I worked on first, and it seemed to to be the one I did last that didn't work. ( I hope this makes sense) The way it works out is as if I got 2 bad bulbs from 2 packages.

 

So you have a defective bulb! Replace it already. $hit happens ya know.