Arrived on site to customer complaint that units would randomly start blowing heat while set on cool. Cycled units through heat, cool and emergency heat. All systems operating properly with appropriate supply and return temperatures. Was unable to re-create symptoms. Found safety switch for unit two wire to brake Y. Rewired safety to break our, that way if problem is an intermittent drain issue thermostat will go blank. Pictures in CompanyCam all systems operating properly at time of departure.