Disposal with pneumatic air switch does not respond when the air button is pressed; LED flashes once-long, twice-short.

Safety first: Turn off power at the breaker before working under the sink.

• Inspect the air tube: Trace the small plastic tube from the sink-top air button to the McAlpine air switch module. Ensure it is firmly connected at both ends and not kinked or split.
• Test the air button: Press the button and listen for a faint puff of air at the module end. If none is heard, replace the button and tube assembly.
• Check the air switch module: With power off, ensure the module is securely mounted and its electrical connections to the motor are tight.
• Bypass test (qualified only): A qualified electrician may temporarily bypass the air switch to confirm the motor runs. If it does, replace the McAlpine air switch module.