One of my tail lights does not work when I step on the brakes (driver side). But when I turn on the headlights and etc, they all work fine but when I step on the brakes again, the driver side still stays a dull red color; while having the passenger side being lit up bright red. Why is this? Anyone help please? Tried searching couldn't find anything.

 

Your high light filament is burnt out. Just replace the bulb. /thread

 

get an 1157 and you'll be good to go