Complete 2 Systems worked on DS Goodman HP Split System. HO stated her DS system was not cooling. She has a nest thermostat for DS. Turned system on cool mode. Found reversing valve deenergized. Checked setting in thermostat, they were fine. HO said the nest thermostat was 3rd tstat she has replaced for the system. Checked continuity on the orange wire, the one coming from outdoor unit to AH, and the one from AH To TStat. Nest thermostat is bad. Sending only 4 volts to outdoor unit. Had to talk to BJ to get info about coverage on the thermosta I was told to replace it with a programmable proselect thermostat. Replaced thermostat with a prog thermostat proselect from truck stock. Checked pressures system is running great at this time.