My airconditioner runs cold one minute hot the next. on 2005 Chrysler Pacifica

I have had it tested. It has enough coolant. We changed the in cabin filter... still off and on cold.. It blows fine just not able to count on the airconditioner to work.

Asked by for the 2005 Chrysler Pacifica
poss high or low pressure switch is starting to fail. what are the low and high pressure readings when its working good?