My 2014 SE Outlander's left brake light stopped working despite the running light (same bulb) working just fine. When the running lights are on, it looks normal. When I depress the brake pedal, it stays at the same brightness while the right one correctly gets brighter. If the running lights are off, the left tail light does nothing and the right one turns on as expected. I checked the 'STOP' fuse and it looks fine - which makes sense since the right tail light is working fine. I took off the left tail light and the bulb and wiring appear ok. I checked all of the other lights on the car inside and out and they also appear fine. I found a thread on here for basically the opposite problem, running light out but brake light worked, and the fixes were either a corroded wire or fixing another bulb that happened to be on the circuit. Any thoughts? Anyone know what else is on this circuit? Thanks.

 

Turns out it was the bulb. I guess double filament bulbs can have a problem with only one filament.

 

I was just working on your opposite problem yesterday. My 2015 Outlander's left taillight won't illuminate after I bought a new bulb to fix it. I also replaced both license plate lights after reading another post.
The left brake light is now working. But, the tail light refuses to come on. I also verified the number 14 fuse is not blown.
The right hand side taillight and brake light both are working normally.
Still confused.