Parts for Thermador CM301B: 03 - Upper Plenum Parts

This replacement fan restores proper airflow inside your appliance, circulating air for cooling and overall performance. Replacing a worn or damaged fan helps keep temperatures in check and reduces noise from rubbing or imbalanced blades.

• Circulates air as designed to cool components and move heat/moisture where intended
• Common symptoms of a failing fan include loud scraping or rattling, weak or no airflow, wobble, or the fan not turning
• Heat buildup around the control area or repeated thermal shutdowns can point to a fan issue
• Physical cracks, broken fins, or warping indicate the fan should be replaced

• Disconnect power at the breaker; allow the unit to cool completely
• Access the fan per your model; remove panels/guards carefully and note orientation
• Transfer any retaining nut/clip or gasket from the original as required; seat the fan fully and secure
• Spin by hand to verify free movement; ensure no contact with shrouds before restoring power

This door switch interlock assembly is the door latch switch that detects and secures the dishwasher door so cycles can start and run safely. It restores proper door sensing and locking for normal operation. What it does:

• Detects when the dishwasher door is fully closed so the control will allow a wash cycle to start.
• Locks or interlocks the door during operation to prevent accidental opening and stop leaks.
• Helps resolve symptoms such as the dishwasher not starting, control lights flashing, or cycles stopping when the door is closed.
• Works as the electrical/mechanical interface between the door and the appliance control.

• One door switch interlock assembly

• Disconnect power to the appliance (unplug or shut off breaker) before beginning repair.
• Remove the dishwasher door panel or access panels as required to reach the latch; keep screws/fasteners organized.
• Align and secure the new interlock assembly and test door engagement and cycle start before reassembly.

This transformer provides the low-voltage power supply required by the appliance control system, enabling proper operation of the control board and related low-voltage circuits. Replaces a failed or noisy transformer to restore reliable control power. What it does:

• Steps down mains voltage to the appliance's low-voltage control circuit for the control board and relays
• Helps restore control functions when a failed transformer causes no power, intermittent control operation, or unresponsive electronics
• Prevents control-board brownouts by providing consistent low-voltage feed (when the transformer itself is the issue)
• Used wherever a dedicated appliance control transformer is required by the appliance's electrical system

• One replacement transformer

• Always disconnect power to the appliance before accessing electrical components
• Verify wiring locations and terminal IDs before removing the old transformer; label wires if needed
• Transfer mounting hardware and brackets from the old part unless new hardware is explicitly included

This replacement transformer cooling fan circulates air to keep the power transformer cooler, helping maintain reliable operation and reducing heat-related stress on electrical components. Fits applicable Bosch appliances that use the 00487021 fan. What it does:

• Circulates air around the power transformer to dissipate heat.
• Helps prevent transformer overheating and heat-related failures.
• Can reduce excessive humming or intermittent operation caused by a failing cooling fan.
• Restores proper airflow that keeps nearby electronics within intended temperature ranges.

• Always disconnect power to the appliance before beginning any repair.
• Remove access panels and mounting hardware to replace the fan; note wiring orientation for correct reconnection.
• Handle the fan motor and blades carefully; avoid bending blades or damaging the connector.

This air interlock is the airflow switch that helps monitor and control dryer vent airflow, ensuring the appliance only runs when proper air movement is detected. It replaces a worn or failed interlock to restore normal vent sensing. What it does:

• Senses airflow through the vent and signals the control system to allow or stop operation
• Prevents dryer from starting or continuing a cycle when airflow is restricted
• Common symptom: dryer fails to start, stops mid-cycle, or shows poor drying performance
• Can help address intermittent operation caused by a faulty vent sensing switch

• Disconnect power before servicing to avoid electrical shock
• Handle the switch and wiring gently; verify connector orientation before reinstalling
• Confirm venting is clear and intact when replacing this part

This microwave high-voltage capacitor replaces the internal capacitor that stores and supplies the pulse of energy needed for the magnetron to generate microwaves. Restores proper HV circuit operation when the capacitor is faulty. What it does:

• Stores and releases high-voltage energy used by the microwave's magnetron
• Commonly fails after electrical stress, age, or arcing
• Symptoms of a failing capacitor: microwave not heating, intermittent operation, humming or arcing noises, or blown fuses
• Works with the high-voltage circuitry—do not use as a general-purpose capacitor

• Disconnect power and unplug the appliance before any service.
• Capacitors can retain dangerous voltage even when unplugged—discharge safely using an insulated discharge tool.
• Follow the appliance service manual for correct removal and wiring; replace with the exact OEM part.

This diode is a small rectifier used on the appliance control electronics to allow current to flow in one direction, protecting the board and enabling proper control signals. Replacing a failed diode restores correct circuit behavior. What it does:

• Provides one-way current flow on the control board to prevent reverse voltage
• Protects sensitive electronics from backfeed and voltage spikes
• Can prevent control errors caused by a shorted or open diode
• Commonly replaced when control circuits fail to power or behave intermittently

• Disconnect power to the appliance before accessing controls to avoid shock
• Handle circuit boards and components with ESD care; avoid touching traces and contacts