E5 error; compressor may not start or may run continuously; temperature control erratic.

Safety: Unplug the freezer. The compressor area contains live mains connections; only proceed if you are competent with electrical work.

• Access compressor compartment: Remove the rear lower cover to expose the compressor, start device, and control box.
• Inspect visually: Look for burnt marks on the compressor start relay/PTC, melted connectors, or signs of overheating.
• Check connections: Ensure all spade connectors are tight on the compressor terminals and relay.
• Test the start device: Remove the relay/PTC from the compressor and shake it gently; if it rattles excessively or smells burnt, it is likely faulty. Measure resistance according to Zanussi specifications if available.
• Measure compressor windings: With the relay removed and power disconnected, measure resistance between the three compressor pins. You should see three different low resistance values; any open circuit or short to earth indicates a failed compressor.
• Replace faulty parts: If the compressor tests good, install a new compressor start relay/PTC. If the compressor windings are faulty, the compressor must be replaced by a refrigeration technician.
• Control board: If the relay and compressor are good but the compressor never receives power, the main control PCB relay may be defective and require replacement.

Because this involves sealed-system components and mains voltage, consider using an authorized Zanussi service provider.