Description
BSM B4 DELPHI for PEUGEOT and CITROËN vehicles. This is a used part with a guarantee of functionality. Some mounting brackets may be damaged — this does not affect functionality.
The BSM B4 Delphi is a body system module designed for certain Peugeot and Citroën models to manage a range of vehicle body functions such as lighting circuits, central locking signals, wiper control, horn and certain safety-related relays. Supplied as a used unit with confirmed operational status, this module is an economical replacement for workshops and DIY mechanics working on affected Stellantis vehicles. Key search identifiers for faster lookup: BSM B4, Delphi, 9644038580, 6500Y1, 6500Y3.
Technical information
- Manufacturer: Delphi
- Model: Citroën C8; Peugeot 206; Peugeot 307; Peugeot 807
- Product Codes: 9644038580, 6500Y1, 6500Y3
- Additional Numbers: BSM B4
Replacement Procedure
General replacement steps: Always work with the vehicle battery disconnected. Locate the BSM module (typically mounted in a fuse/control module area inside the passenger compartment or engine bay depending on model), remove any trim or protective cover, unplug the electrical connectors carefully using a locking-tab release, unbolt the module from its mounting points, install the replacement module in the same orientation, reconnect the connectors and secure all fasteners. Reconnect the battery and verify vehicle functions controlled by the BSM (lights, central locking, wipers, horn, etc.). If multiple systems are affected after replacement, check fuses and ground points prior to further diagnosis.
Installation Recommendations
- Disconnect the negative battery terminal before any work to avoid short circuits and to protect the module and vehicle electronics.
- Handle the unit by the housing and avoid contact with connector pins to prevent corrosion or electrostatic damage.
- Inspect and, if necessary, clean connector contacts and housing seals to reduce risk of poor connection and moisture ingress.
- Secure mounting points even if some plastic brackets show cosmetic damage — ensure the module is stable and protected from vibration.
- After installation, perform a functional check of all circuits controlled by the BSM and clear any stored fault codes according to the vehicle manufacturer’s procedure.
Why This Part Most Commonly Fails
BSM modules typically fail due to environmental and electrical causes rather than mechanical wear. Common reasons include moisture ingress and corrosion at connector pins, electrical surges or poor vehicle battery/charging conditions, cracked solder joints or aged relays inside the unit, and physical damage from improper mounting or impact. Damaged plastic mounting tabs are common on used units and usually cosmetic, not affecting electrical function, but they should be assessed to ensure secure installation.
Notes For Mechanics And DIYers
When searching or ordering, using the product codes (9644038580, 6500Y1, 6500Y3) will speed up identification. This used Delphi BSM B4 is suited for professional workshops and experienced DIY mechanics comfortable with vehicle electrical diagnostics and proper safety procedures. Verify vehicle-specific procedures in the manufacturer service manual before coding or testing functions.
