Headlight Bulb

Well, my passenger headlight bulb went out yesterday (warning light came on). I went down to the local auto parts store and picked up the Sylvania Cool Blue h7 bulb. I replaced both bulbs (replaced the driver side bulb as well just as precautionary measure). I turned on my lights and now the passenger side bulb is a whole lot brighter than the driver side.

Why is this? Could this be because when the bulb on passenger side was put back, it was not exactly in the center of the headlight assembly (in other words, slightly off). When I turn off the headlights and look at the position of the bulb, the passenger side does not appear to be exactly in the middle of the assembly as the driver side.

Any input is appreciated! Thanks!

That could be the answer, you have to try to get the bulb in the centre. If you look closely (with the lights off) do they look the same, do you see the half-cups on both that covers half of the lamp, or is the passenger side one missing ?

You did not apply pressure to the light unit, pushing it out of setting/alignment perhaps ?

Another possibility ... the electrical connections/earth can be out of whack on the driver's side ... not properly grounded.