My bathroom shower has no cold water only hot. What can be the cause of this and what's the fix?

My bathroom shower has no cold water only hot. What can be the cause of this and whats the fix?
Shut the water off to the shower valve and open it up. Check and clean the inlet ports on the cartridge. Now turn the water on for a minute to flush out the valve body and supplies. You should have a strong stream of cold water out of the open valve body when you do this. If not then click on back. Good luck, Tom