Hoping somebody has had this same issue before-

On the rear end lights, when I actuate the brake switch:
1. the outside 2 lights function correctly.
2. the inside tail lights turn off.

Additional info:

Regular running lights (no brake mode) illuminate on both sides, however:

1. the inside 2 tail lights get brighter when i physically install the lamps into the housing (they get good ground).
2. in other words, with the lamps out of the housing, the inside set of tallights work at the proper brightness (low). When i ground them, they go into "brake" mode (bright)..

Assumptions:

1. There must be a ground feedback somewhere on the lamp harness between the two hot wires in the socktet, because I understand the two wires in the center of the socket are for 12v (one running lamp, one brake/turn), and the tab on the rim of the socket is supposed to be the ground. Therefore, they must be in brake mode all the time, and are simply going brighter when you plug them in because then they get a good ground?
2. I suspect a turn signal wire may be wrong at the column? It's a new harness from the guys at Columns Galore- but I haven't pinned it out or investigated the turn signals, etc.

Any ideas?

Thanks!

Mike

It could be a combination of bad ground at the taillight housing and crossed filament wires. Something to consider, when you have one socket removed, you don’t have proper taillight grounding in the system, so any “results” you conclude from such an electrical test is beyond flawed.

+1 ... poor ground or the filaments swapped.

However, did it work ok and is now faulty? If so, could also be something with the indicator switch... what happens if you unplug the flasher can under the dash (not the flasher can on the fuse panel which is for the hazards)?