Toilets, Sinks, Showers, Tubs and Disposals - Delta single lever shower valve-no hot water

About two years ago I installed a single lever shower/tub valve. The type you rotate c-clockwise. At about 90 degrees, the hot water kicks in. It's been working fine until recently. We've got plenty of cold but as soon as you get past the 90, the water just slows to a trickle. Not even enough to keep the shower diverter up. I tried opening the stops with the valve cartridge out to see what I had for water pressure, but got nothing on either side. I swapped the rubber cups and put it back together and no change. I have a single lever at the lav and it works fine. It's late, my GF wants to take a shower and it looks like I'll be sleeping in my car tonight-HELP:wall:

Not sure I understand. You do not get water flow with the cartridge removed and you open the shutoff valves?? That is not right, you should get full pressure, and I might add, all over the place. But the usual cause of the problem you decsribe is the cartridge.

Call Delta--I believe that cartridge has a lifetime warranty.
I don't think you opened your shutoff valves-otherwise you would have flooded the area. Is the cartridge a grey color?
You will need model # stamped on side of cartridge--like T0508-c also
the ser. # below that..................