Did you check the bulb?
That's when my shifter was messed up too, I really need to take the minute it takes to correct it Hope it works for ya.I'll try the shifter thing. This problem started after I replaced the chain and sprockets, so maybe that's it, since I did have the front sprocket cover off. I thought I put the shifter back on just as it came off though and it seems to shift just fine too. I'll check it out anyway though just to be sure.