I've searched the postings, but haven't found this discussion.
Right rear brake light went out, got the message on the dash. No problem - put in a new bulb. Original bulb looked pretty good though and, sure enough, new bulb did not solve problem.
Swapped bulb mounts; right rear brake light still out. Left works fine, so I know the bulb and housing are fine.
Checked voltage across housing with bulb/mount out - no reading until brake pedal applied, then 13V.
So, I'm stumped. I've got voltage, and a bulbs/mounts that works on left side, but not on the right side.