How to Fix / Troubleshooting

Safety first: Disconnect power before internal inspection.

Step 1 – Check ventilation: Ensure the Thermador microwave has proper clearance and that cabinet or trim vents are not blocked.
Step 2 – Clean filters: For over-the-range models, remove and clean grease filters to improve airflow.
Step 3 – Listen for fan: Confirm the internal cooling fan runs during operation. If not, suspect a fan or control issue.
Step 4 – Inspect thermostats (qualified persons): Remove the cover and locate thermal cutoffs and thermostats on the magnetron and cavity. Check for loose connections or signs of overheating.
Step 5 – Replace faulty components: Replace any open thermal cutoff or failed fan motor with Thermador OEM parts.

Note: Repeated thermal trips indicate an underlying cooling problem that must be corrected.

Microwave cavity light and fan come on, but the unit shuts off after a few seconds without heating.

Possible Causes