Dash AC intermittently blowing cold air, then hot

I had that problem with my Rexhall with the Evans Tempcon Electronic Control. It got to where the control would not shut off after getting hot. I solved the problem by replacing the electronic controlled valve with a cable operated valve. Have not had any problems since. It was a fairly simple conversion for me, for someone that is not mechanically inclined it may be very difficult as the control panel must be modified or a cable control panel be purchased. JMO