I decided to tackle my pathetically dim tail lights by swapping the US lenses out for euro ones, and installing Spokeworks LED lights. I started by removing the tail light housings to power wash behind them to remove all the grime and gravel. Hot water through the pressure washer had me laughing at how easy it was to blast away all the grime. Very satisfying project.
When I reinstalled the housings, bulbs, and lenses, I discovered that my brake lights wouldn't light up when I pushed on the brake pedal. The passenger side markers didn't work either. Figured I had screwed something up while pressure washing so I took it all apart and verified the connections were tight and the wires weren't damaged. No issues there. After a whole bunch of troubleshooting, it turned out to be BOTH of the brake switches on the master cylinder had failed. You can see the switch closest to the master cylinder here:
I verified the switches were the problem by jumping one of them and testing the brakes, which then worked fine. After replacing the switches (and bleeding the brakes), everything worked except for the side markers. Those ended up being due to a failed diode under the dash. This diode was apparently only on the '86 year model and no one really knows why it's there. I was able to track down a new one which fixed the last of the light issues.
After my new LED's arrived from Spokeworks, I got them installed in about 30 minutes.I don't have any good before and after pics, but the difference in light output is huge. The pic below has all the lights on. I had the car in reverse and snapped the pic while the turn signal was illuminated (brake lights were not activated, just the night time running lights).
Very nice to have tail lights that can actually be seen!