My newly purchased used bike has Shimano SIS shifters. The left one has a sticker saying "Light Action", and they have model number SL-RS30 printed on the bottom side.
I need to open them, because they do not work, but I can't find out to get them opened. There is one screw on the bottom of each, and when that is loosened, the shifter can be slided off the steer bar. But I cannot open the shifter box itself.
Does anyone know a magic trick on how to open the shifter box? (and yes, I tried "Open Sesame!" but it still wouldn't open)
Here are two pictures of the shifters, the last one including my left foot (taken with my phone, so sorry about the quality --of the pictures, not my foot):
Thank you all for your help. I bought the bike on a Lost & Found auction, so there is no one I can return the bike to. But if my problems with the shifters can be solved by adjusting the cables that sounds like an easy solution, so I will try that first. Park Tools' guide seems very user-friendly with pictures and all, so I think I might even have a chance on making it work.