Our shower was working fine for a couple years but started periodically only producing hot water ( single handle american standard /am 11. cartridge ) but no cold. All other fixtures in bathroom still have cold water. I replaced the cartridge but still have the same issue. As a side note, the hot water comes into the valve body on the right side (not left as is usual). It has always been like this.
Possibly whoever originally installed the shower valve realized that the hot and cold supplies were switched and they installed the cartridge in the valve in the opposite orientation than normal. This made the control work in the usual way. When you replaced the cartridge you installed it in the correct orientation for hot on the left and so it no longer longer works