Generator starts automatically on power loss but transfer switch does not move to generator position; house remains on utility or dark.

Safety first: Only qualified persons should open and work inside transfer switches. Turn off all power sources and verify with a meter before touching conductors.

• Listen for operation: During an outage test, listen for the ATS contactor to move. No sound suggests a coil or control issue.
• Inspect control cable: Check the low-voltage control cable between the Guardian generator and ATS for damage or loose connections.
• Manual operation test: With all power off, attempt to manually operate the contactor (if design allows) to check for mechanical binding.
• Coil voltage check: During a start command, measure coil voltage at the ATS. If present but no movement, replace the contactor assembly.