Is the cable broken? You have to be on the bike and pedaling to get them to move, They are pretty simple mechanical things, the only that can go wrong is a broken cable, and maybe out of range stops. It will cause the chain to fall off one end or the other, There are little screws that stop it from going too far. Thumb shifter too tight? Check it out.
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Is the cable broken? You have to be on the bike and pedaling to get them to move, They are pretty simple mechanical things, the only that can go wrong is a broken cable, and maybe out of range stops. It will cause the chain to fall off one end or the other, There are little screws that stop it from going too far. Thumb shifter too tight? Check it out.