:confused: and in a hurry. I have a one handle shower on/off temperature control valve and it has worked fine for last year. Recently I replaced much of the plumbing in its original configuration and the water heater. I took the valve off to replace the pipes going in hot and cold and the lines to the shower head and tub spigot. Now when I turn the water on to the tub water also comes out the shower head. I can pull the knob on the tub spigot to make all the water come out of the shower head but then when I push it down water comes out the tub spigot and still out of the shower head. I took the tub spigot off and let water gush out of the tub pipe and it did not change the flow out of the shower head. I replaced the regulator valve in the valve body ( only to realize it regulates the mix of hot and cold water. I used thread paste in all of the connections on the valves. Could I have a blockage in the body somewhere that is causing this? Does anything go on in the body? The valve is a pfiser or something like that. I am quite desperate as I cannot sheet rock the wall and finish the kitchen remodel until I get this resolved.

Sounds like you have a bad diverter spout. Since they are so inexpensive why not simply replace it? What type diverter spout do you have? A chrome over plastic slip on or a chrome over brass screw on one,(see images)?
Do you need helping replacing it? Regards, Tom