960 Brake Light and Corner Light Issue

[Wackneck]

Hi all, I have a 1993 pre-facelift 960 wagon. I was driving home today and my left brake light had stopped working, so, as one does, I exercised a little percussive maintenance - I smacked the housing and it worked. Shortly after the light went out again, I thought all it needed was another hit, but it didn't work this time.

I then struggled thru the rear panel to have access to the back of the light column housing and put a new bulb in, which technically should've been the end of the story, but then I realized it still didn't light up (no daytime light and no brake light) and now the front corner\parking light is also not lighting up. What is going on??