Originally Posted by Diseasel300

The monovalve is bad or the CCU isn't sending voltage to the monovalve coil. It's as easy as that.

Start with the monovalve cartridge. Buy OEM only, Aftermarket will leave you disappointed. The OEM part is less than $40 and commonly fails. If the cooling system isn't maintained, it'll rust and seize in place. If $40, 4 screws, and 30 minutes of your time is too much to ask, drive with the windows down.