1996 850 Taillights: outer bulbs are dim, altitude issues

[Ubbm]

!996 850 Turbo:
The outer of the 2 taillight bulbs on each side is quite dim, the inner on both sides are burning nice and bright. Has anyone had this problem? Yes, I replaced the four bulbs with a matched set.

(Previous unsolved problems: Cruise control works up to about 7000 feet then quits. The automatic transmission locks and won't shift above 9,000 feet. Guess I should move to the flat lands!).