Thermostat or control module shows E6 and the indoor blower runs but the outdoor unit does not

Safety first: Turn off power to both indoor and outdoor units. Low-voltage circuits can still be damaged by shorts.

• Check low-voltage cable: Inspect the thermostat/control cable running from the air handler to the outdoor unit. Look for cuts, chew marks, or UV damage. Repair with proper splices or replace if severely damaged.
• Inspect low-voltage fuse: On the indoor control board, locate the 3A/5A blade fuse protecting the 24V circuit. Replace only with the same rating if blown. If it blows again immediately, there is a short that must be found.
• Check contactor coil wiring: At the outdoor unit, verify that the two small-gauge wires from the indoor unit are firmly connected to the contactor coil terminals. Tighten loose spade connectors.
• Test operation: Restore power and call for cooling. If the contactor does not pull in and E6 remains, the outdoor control board or contactor coil may be faulty and should be tested by a technician with a multimeter.