Generator runs but produces no AC power at the house; lights and appliances remain off even though engine is running.

Safety first: Keep the generator running unloaded by leaving the main breaker open while you diagnose. Use proper PPE when working in electrical panels.

• Check generator main breaker: Open the enclosure and verify the Guardian main breaker is in the ON position. Reset if tripped.
• Measure voltage at lugs: With the main breaker ON and extreme caution, measure voltage at the generator output lugs. If correct voltage is present, the issue is likely in the transfer switch or house wiring.
• Inspect transfer switch: Verify that the ATS is switching to generator position when the unit runs. Listen for the contactor to operate and check indicator lights.
• Loose connections: With all power off and locked out, tighten all lugs in the generator and transfer switch.
• Professional service: If there is no voltage at the generator lugs, the stator or AVR may have failed and should be tested and replaced by a Guardian technician.