Dryer does not heat properly and displays E04; cycle ends quickly with damp clothes

Safety first: Disconnect the appliance from mains and wait for internal components to cool before accessing the rear panel.

• Access heater assembly: Remove the rear panel (or side panel on some Grundig models) to expose the heater housing and wiring.
• Check wiring: Inspect all heater connectors for signs of burning, discoloration, or looseness. Reseat any loose connectors firmly.
• Test heating element: Disconnect the heater terminals and measure resistance across the element with a multimeter. A very high or infinite reading indicates an open element that must be replaced.
• Check thermal cut-outs: Locate the thermal cut-out(s) or thermostats mounted on the heater housing. Test for continuity. If open and non-resettable, replace the faulty thermostat/TOC. If a manual reset type is fitted, press the reset button if present.
• Reassemble and test: Refit panels, reconnect power, and run a warm cycle. If E04 persists and the heater circuit tests good, the heater relay or main PCB may be defective and professional diagnosis is advised.