Description
Mechanical heating and air conditioning control BEHR for Citroën C4 and Peugeot 307.
High-quality manual HVAC control unit manufactured by BEHR, commonly referenced under codes B5RF, 6451VK and B9642. This climate control panel is intended for mechanics and experienced DIYers who need a reliable replacement part for Citroën C4 and Peugeot 307 vehicles. The unit provides intuitive mechanical control of temperature, fan speed and air distribution, with robust rotary controls and sliders designed for everyday use. Often searched by product codes B5RF and 6451VK, this part helps restore full HVAC functionality when original controls become worn, sticky or mechanically damaged.
Technical Information
Manufacturer: BEHR
Model: Citroën C4; Peugeot 307
Product Codes: B5RF; 6451VK
Other Numbers: 6451.VK; 6451VK; B9642
Function And Application
This mechanical control module operates the vehicle heater and air conditioning system functions such as temperature selection, blower speed, air distribution (dash/foot/windshield) and recirculation. It translates the driver’s inputs into movement of internal linkages, cables or electrical signals (depending on the vehicle’s configuration) to actuate blend doors and blower controls. Designed as a direct replacement for the original unit used in many Citroën C4 and Peugeot 307 models, it restores tactile control and accurate regulation of cabin climate.
How To Replace
Replacement is straightforward for a trained mechanic or competent DIYer with basic hand tools. Typical steps:
- Remove the center dash trim surrounding the control panel to access fasteners.
- Unscrew the retaining screws and gently pull the unit forward to access connectors and control cables.
- Unplug the electrical connector(s) and release any Bowden cables or linkages, noting their routing and attachment points.
- Install the new control unit by reconnecting cables and connectors in the original positions, secure with screws and refit the trim.
- Check all functions (fan speeds, temperature adjustment, recirculation and air distribution) before final reassembly to ensure correct operation.
Installation Recommendations
- Work methodically and keep small screws and clips organized to avoid damage or loss.
- Before disconnecting electrical connectors, make sure ignition is off and follow safe workshop practices.
- When detaching or reattaching Bowden cables, do so carefully to avoid kinking or incorrect routing which can cause poor control response.
- Verify fuses and blower resistor if fan speeds are intermittent or non-functional, as multiple components can cause similar symptoms.
Why This Part Fails Most Often
Common failure modes for manual HVAC control units include mechanical wear of knobs and internal linkages, degradation of plastic gears or sliders, and contamination from dust, dirt or spilled liquids that cause sticky or intermittent controls. Prolonged sun exposure can embrittle plastic components, while repeated use over many years accelerates mechanical wear. Electrical contacts for fan speed or switch functions may also become corroded or worn, leading to loss of specific blower speeds or unreliable operation.
Practical Tips
When diagnosing HVAC faults, inspect switches, cables and connectors before replacing the control unit. Symptoms such as no blower at any speed, only certain speeds working, or stuck temperature sliders can point to either the control unit or related components (resistor pack, blower motor, cables). Replacing the control unit typically restores full manual control when the original panel is mechanically damaged or worn.
