Bosch Relay / Contactor Chatter or Start Failure

Unit emits clicking sounds repeatedly but does not start cooling or heating.

Advertisements

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.

Advertisements

Possible Causes

Low supply voltage, Faulty relay on outdoor PCB, Compressor locked rotor, Loose control wiring

How to Fix / Troubleshooting

Safety first: Clicking relays indicate repeated start attempts; prolonged operation may damage components.

Steps:

  • Turn off unit: Switch off the Bosch AC and breaker to prevent further stress.
  • Check supply: Ensure the unit is on a proper circuit and not sharing with heavy loads.

Technician actions: Measure supply voltage, test compressor, and inspect relays/contactor on the outdoor PCB. Replace faulty components as needed.

Advertisements

Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Control / Relay PCB
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements