Responded to no cool. Customer said it froze up. They let thaw for 24 hours and now thermostat states waiting reading sensors. Customer replaced filter and stated it was very dirty. Believed to be reason for freezing. Found good pressure with low subcooling. Dirty condenser. Offered to clean unit. Stated they will wash unit. Found thermistor had bad connection at heat pump. Replaced wire nuts and ensured good connection. Thermostat reading 91. 86 ambient temperature with sensor in sunlight. Accurate reading on stat. Unit cycled on properly multiple times