When I turn on the control I get nothing but a luke warm to cold temperature in any position up to the middle of the rotation area.when I turn the knob completely to the left / hot side water goes to barely a trickle and the feel of the valve is comparable to the feel of shutting of the cold.
This is a Mowen tub and shower valve that did work but has changed. The house was built in 2007

Shut the water off under the cabinet ands open up the faucet. Remove the cartridge and check and clean the inlet ports. While the valve's open place a pan over it and turn the water on to flush out the supply. You should have a full sream when you do this. If not let me know. Good luck, Tom