87 5kCSTQ Mysterious Brake Light

[Joshua Van Tol]

>So, during the year storage in the back yard, I bashed a quarter-sized hole
>in the right rear taillight assembly on the Gray 87. Chris Semple sends me a
>new taillight (thanks, Chris). I install it last night. Easy to do with deep
>8mm socket. Hardest job is reworking the sticky black goo used to keep water
>out. I go for a test drive and on comes the warning light telling me my
>brake lamp is kaput. I go around to the rear of the car, having son press
>brake pedal. Sure enough, the brake light no longer lights. I know it
>worked, since the car just passed the state safety inspection. So I figure
>the light bulb must have coincidentally burnt out. No, filament still good.
>I check all the fuses, Nope.
>
>Then I turn on the headlights. Now the mysterious behavior. The brake light
>now comes on with the taillight! Other brake lights work normally, but this
>one now only comes on with taillight and fails to work as a brake light.
>
>No connectors were removed or reattached in the lens replacement process.
>The bulb carrier just snaps out then snaps back into the new lens assembly.
>There is no electrical contact between the bulb carrier and the lens
>assembly, so it can't be a ground problem.
>
>What gives?

That bulb cluster probably has a 1 filiment bulb installed in a two 
filiment socket, or a bulb installed backwards. It's hard to do, 
because the little retaining tabs prevent it, but sometimes people 
just cram them in.
-- 
Joshua Van Tol -- josh at spiny.com