22FEB2024 Jason Brown Arrived for previous customer and recent install not cooling well. Spoke with the homeowners about the issue. This has been consistent for the last couple years. You guys find things wrong but never catch this one. At night the system will cycle on then off then before the fan cycle is over come back on. It will do that until we switch the thermostat into the off position. Inspected AC, furnace and new evap coil. Verified electrical connections and all components. Inspected nest wiring. Found thermostat operating without a C wire. When the thermostat does not have a C connected it will use y or w for a common wire depending on which mode the system is operating in. When it cycles off it defaults back to the y wire causing the system to cycle on. I connected the c wire then cycled the equipment several times. After discussing my findings with the homeowners we all cycled the system on and watched it turn off. This is an intermittent issue however so things may stil