Brake light Issue

[LeggyxPower]

Alright, i am having an issues with one of my brake lights. its the inner (one of the trunk) passenger side
-when brake pedal is pressed with lights off, it is noticeably dimmer then the rest of the brake lights
-when lights are one and brake is pressed the light completely goes out. but when brake isn't pressed its back on and has the brightness just like the rest of the lights.

-All other lights are in perfectly working condition except this one

i already changed the bulb,checked the socket and checked surrounding wires..
Could it be a bad ground near the 3rd brake light?

[awesomefacespacebear]

Bump. Same exact problem, did you figure out what was wrong? I heard bad grounding is a possibility but where do I check? Basically no electrical experience