I need advice/help in how to figure out why the water does not come out the bathtub faucet but only from the shower head. It is an older house with a three handle system. When the hot and/or the cold water is turned on, the water comes from the shower head. The middle handle, which I assume is to direct the water from the faucet to the shower head, does nothing when turned. I would like to correct the problem myself if possible, even though I am a novice at this, money is an issue and cannot afford a plumber. Thanks!