Freezer shows E9; compressor may run continuously or not at all; temperature is unstable

Safety: Unplug the freezer before accessing the compressor compartment. High voltage and hot surfaces are present.

Steps:

• Inspect wiring: Remove the rear lower panel and check all wires to the compressor, start relay, and control board. Tighten any loose spade connectors.
• Check for visible damage: Look for burnt wires, melted insulation, or scorch marks near the compressor terminals and on the control board.
• Test compressor windings: If equipped and trained, use a multimeter to measure resistance between compressor terminals. Very low or uneven readings may indicate a shorted compressor.
• Board inspection: The current sensor is often integrated on the main PCB. Inspect for burnt components near the compressor output. If damaged, replace the main control board.
• Reassemble and test: After correcting wiring issues or replacing parts, restore power and monitor operation. If E9 returns, professional diagnosis of the sealed system is recommended.

Warning: Do not attempt to open the sealed refrigeration system yourself; this requires specialized tools and certification.