Headlights out of aim because of defective new bulbs?

I have an old Mazda MX-3, which uses the 9004 headlights. (It’s probably been many years since a car was made that used 9004’s; they’ve been superceded by better dual filament bulbs like the 9003.)

The aim seemed to be OK, but the low beams didn’t give much of a view of the road. I read in a few Internet forums that GE Nighthawk bulbs were one of the better ones, so I bought a pair on eBay for about $20.

The car’s plastic headlight shells were a bit yellowed, so I polished them and then replaced the bulbs with the new Nighthawks. Imagine my surprise when the lights now seemed out of aim! The light on the road was more scattered and uneven, and some of the light was awfully far to he left when I shone the lights onto a garage door.

In the past, polishing the headlights did not affect the aim. That makes me suspect the new bulbs. Has anyone ever gotten headlight bulbs that didn’t aim properly?

I still have the bulbs I replaced. They both worked, so I kept them in case of an emergency. I swapped them back into the headlights, and the next time I drive in the dark, I’ll see what the aim looks like. I already shone them onto the garage door, and the beam does seem more focused than with the new ones.

Are you sure the bulb went in correctly? The base should have an indexing tab on it, so it will align the low beam filament properly. The high beam filament is generally located in the center and the low beam offset to direct the beam down. If the bulb were installed with the low beam in the incorrect position, the beam could be directed up, left, or right. This assumes the headlights are correctly aimed. Over time, the aim can ‘creep’. The headlights always seem to need periodic aiming. I always check and adjust the aim when I replace bulbs.

9004 are not superceded.9004 is a dual fillament bulb.I have some for sale on my shelf today.
9003 are wrong. ( 3 tab metal base )
9007 kinda look the same but are notched different & won’t fit.
What number bulb did you get ?

Force fitting the wrong bulb will put the fillament in a different alignment with the reflector and lens thereby resulting in a different beam line.

On you MX3 did you pull the lens assemblies to polish them or to replace the bulbs ?

By “superceded,” I meant that later model cars starting using different (and better) 2-filament bulbs instead of the 9004. I didn’t mean that you could simply replace a 9004 with something else in the same car. All bulbs I’ve used in this car are 9004’s.

I didn’t remove the lens assemblies. All I did was polish the outer surface of the headlight shell. I had done this at least twice before over the years, and I didn’t notice any effect on the aim before changing the bulbs. This is the first time I changed the bulbs.

I could find only one way to install a 9004 bulb in the headlight assemblies of my car. Any other orientation would not allow the bulb to seat completely to allow the retaining ring to screw down.

( the word ‘superceded’ means alot more to a parts man -me- than usinig different numbers in subsequent models. )

Sounds good so far, now what ?

Did you grab the glass globe of the bulbs while installing them ? This could burn dark from oils on your fingers.

When removed from the package, was the globe straight up from the base ? If the bulb was bent it would misalign the beam too.

Yes, I have had this happen. I replaced one of the bulbs due to failure and found the new bulb caused the low beam aim to be much higher than the factory bulb in the other headlight. Swapping the bulbs L/R caused the problem to move with the bulb. I reaimed the headlamp with the offending bulb.

Are both of your headlights misaimed equally with the new bulbs or is it just one of them?

I didn’t touch the glass part of the bulbs, and they looked clean. Both lights seem to have their light more scattered than with the old bulbs.

I’ll know more when it gets dark and I drive the car again with the old bulbs. And I can try the new bulbs in each headlight, and in various combinations with the old ones.

I also noticed that the driver side headlight was already adjusted as far inward as it could go, and still the new Nighthawk bulb spread a fair amount of its light to the left of the car.

Modern headlight systems are mostly plastic junk…It’s time the DOT requires quality glass sealed beam headlights to be used once again.

For many years, so many people were calling DOT “backward” when they required the large sealed beam lights while Europe had bulbs. The “plastic junk” seems to work fine in the inexpensive Toyota Corolla (4-lamp 9006/9005 system), and newer cars don’t use unfortunate bulbs like the 9004. I think what’s needed is a better standard for how much of the road the lights show for high and low beams. For all I know, DOT standards may have improved since bulbs were first permitted.

I put the old lights back in, and their aim isn’t really better. The driver side light is still a little lower than the passenger side (though maybe it’s supposed to be that way?), and it’s pointing too far to the left. The height is easy to change, but the headlight seems to be pointing as far inward as it can go.

My guess now is that the new bulbs just made the mis-aiming more obvious.

Back when sealed beams were required the best thing I did for my headlights was to replace them with a pair of Marchal non sealed ! Man what an improvement !
Sealed beams were trash .