Coleman air conditioner thermostat display is blank or flickering; system may not respond.

Safety: Turn OFF power to the air handler before working on low-voltage wiring.

• Check breaker: Ensure the air handler breaker is ON.
• Inspect board fuse: Replace a blown low-voltage fuse with the same rating. If it blows again, locate and repair shorts in thermostat wiring.
• Verify 24V at thermostat: Measure between R and C at the thermostat. If no voltage, test at the control board and transformer.
• Secure wiring: Tighten R and C connections at both thermostat and control board. Repair any damaged cable sections.
• Replace thermostat: If power is present but the display is dead, replace the thermostat with a compatible Coleman model.

Note: Some advanced thermostats require batteries; replace them if applicable.