Driver side brake light not working
 

Was told last week that the driver side rear brake light wasn't working. I bought a new one and replaced it but it's still not working, but when I turn on the headlights that area is illuminated. I know it has 2 filament I assume when the brakes are applied they both turn on. I have an 82 with the combo seat belt and brakes warning module on the dash.
The brake light is on now when I release the hand brake. Could it be the brake light switch on the brake master cylinder? Would it effect one side only?
Thanks for any help.

not exactly the same problem, but good advice on grounds, checking for a short in the light under the engine deck lid, which is fed by the driver's side rear signal cluster, and moving bulbs to other side to check/confirm whether issue follows bulb. http://forums.pelicanparts.com/porsche-911-technical-forum/1117611-911-sc-tail-light-electrical-gremlin-can-anyone-help.html

Check/clean the copper piece in the bulb socket where the base of the bulb sits. Might need to be extended a bit to make good connection. Also, check grounds for that light assembly. I had the same issue when I first got my 69E years ago.

I switched bulbs from passenger side to the driver side and now both work.

I did remove the whole tail light assembly yesterday and did see one of the
weird connector ( a kind of circuit board material which is criped to the housing) had come loose.
I did try it again yesterday evening and it didn't work then .

I had the little circuit board come loose on the back of the socket come loose.

Tried epoxying it back. Did not hold. I ended up getting a generic light bulb socket from my local FLAPS and machined the opening to allow a very tight press fit. That was years ago and still working great.