Simple cure water PUSHS out not sucks in, thus you will not get any suction from a faucet as long as the water supply is on.

To create a suction (back flow) you have to shut off the main water supply valve, then open the tap you want the suction and open a tap below and this will cause a vacuum and you can hear the whoosh of air being sucked into the line.

Now if you want to flow out of a faucet not used for a period of time one would shut the water supply disassemble the faucet and check the washer and seat for obstructions and re assemble and test

I will try out your ideas.

TC

I disassembled the faucet, there are no obstructions. The hot water in the sink next to the tub works fine. The water in the tub seems to be only the cold water. When run for a period of time, the water never warms up. Is there a way to release a stoppage from the hot water line without breaking into the tile and exposing the pipes?

TC

Try closing the hot water supply disassemble the the shower body hot side and hold from the basin remove the aerator put your finger over the spout opening tun on the hot side (No water coming out of course

Then turn on the C/W this should flush out anything that may be blocking the supply line

Back flushing sometimes works

good luck