kingston 

I bought my wife this Gazelle on CL a few weeks ago, and I can't get the lights to work. When I got it, the tail light was working, but the front light wouldn't work. Then I took the headlight apart and put it back together. Now the headlight works but the tail light doesn't work. The wiring was the same both times. Any suggestions on what to try to get both lights to work at the same time?

randomgear

Did you manage to reverse the polarity somewhere by attaching the wrong wire to the wrong terminal?