It's very likely that the heater valve is now not working correctly and adding heat to the system causing the refrigeration effect to be overcome.

With everything running and a/c turned on max, feel of the hose going in and the hose going out of the valve. If they are both warm then the heater valve is flowing heated coolant to the heater core and this is probably the trouble.

If not, then you need to check the sight glass and best approach would be manifold gauges to check a/c.

Good luck,