My high mount brake light is not working so I pulled it out for replacement. Upon close inspection, the bulb appears fine. Why won't it work then? Is there any electrical problem causing that? Other brake lights work fine except one parking light (#5) on the driver side. It is brighter than the passenger side so I pull the light assembly out and compare the two. The bulb on the passenger side is not burning with both filliments but it also appears not broken. So I swab the bulb from the driver side and now the bulb is only burning on one filliment in the passenger side light assembly. The bulb from the passenger side, when put into the driver side light assembly, does not sit tight and won't light up. I check the owner's manual and they are the correct bulb. Anyone has any idea? BTW, it is for my newly accquired '96 W202.

__________________
95 R129
04 Infiniti G35.5 BS
10 X204

The bulb could look good, but be bad. If you have a multimeter, check resistance. While you're at it, check for voltage at the bulb socket terminals while a helper applies the brakes.

If you don't have a multimenter, buy a new bulb, it's cheaper than a meter.

Filaments can break, dangle around a work one day and not the next. The break can be nearly invisible to the naked eye.

For the parking lights, first be sure that you have the correct bulbs. Parking lights by themselves are only one filament. Combination parking and turn signal, or parking and brake will have two filaments.

Sockets can loosen, or break, and an open contact means no current, so no lamp function.

Best Regards,
Jim