While running my tub faucet, if I turn the temp handle to the middle, the shower runs as well. The diverter is on the tub faucet position. How do I get the shower not to run?

Is this a one handle or a three handle tub valve?

1 handle

Remove tub spout, turn water on and see what happens.

There are two types of tub spouts, one screws on and off the other has a set screw on the underside that you loosen.

While running my tub faucet, if I turn the temp handle to the middle, the shower runs as well. The diverter is on the tub faucet position. How do I get the shower not to run?
This condition happens when,
1) the shower raiser's too short.
2) There's a partial blockage in the spout supply line, (Very doubtful) **or**
3) You have a PRV valve that's allowing too much pressure in the system.
If you do have a PRV valve that's where I would start. Good luck, Tom

Thanks! Lori