Thermostat shows "Cooling" but only the indoor blower runs, outdoor unit stays off
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power to both the air handler and outdoor condenser at their breakers before inspecting outdoor wiring. Outdoor units contain high voltage and moving parts.
Steps to diagnose:
- Check outdoor disconnect: Ensure the service disconnect near the outdoor unit is fully inserted or switched ON.
- Inspect condensate safety switch: Look for a float switch in the drain line or pan. If tripped, clear the drain and reset the switch.
- Inspect low‑voltage wiring at condenser: With power off, remove the condenser access panel and verify the thermostat cable is securely connected to the contactor coil terminals.
- Test Y circuit continuity (advanced): An HVAC technician can test continuity of the Y circuit from the air handler to the outdoor unit.
When to call a pro: If wiring and switches appear normal, the issue may be with the outdoor contactor coil, control board, or low refrigerant safety circuits, which require professional service.