Description
Engine BSM B2 DELPHI. This is a used part with a guarantee of functionality. Some mounting brackets may be damaged – this does not affect functionality.
The BSM B2 (Boîtier de Servitude Moteur) by Delphi is the engine bay power distribution and control unit used on a range of Citroën and Peugeot models. It houses fuses, relays and electronic control elements that distribute power to lighting, ignition, fuel pump, sensors and other engine-related circuits. This used unit is supplied with a guarantee of functionality; superficial damage to plastic mounting brackets can occur during previous removal and handling but will not impair electrical performance.
Compatibility
Commonly fitted to various Stellantis Citroën and Peugeot vehicles. Known applications include Peugeot 206 and Peugeot 307. Verify fitment against the product codes listed in the Technical Information.
Technical Information
- Manufacturer: Delphi
- Model: BSM B2
- Product Codes: 9644038780, 6500Y1
- Other Numbers: Stellantis Citroën/Peugeot references (see Product Codes)
Function
The unit functions as the engine bay fuse and relay box with integrated control electronics. It routes and protects electrical circuits for engine management, ignition, fuel delivery, cooling fans, exterior lighting and other ancillary systems. A fault in the BSM can cause loss of multiple systems or intermittent electrical problems.
How To Replace
- Disconnect the negative battery terminal before any work to prevent short circuits and protect the unit.
- Locate the BSM in the engine bay (position varies by model). Remove any covers and clear access to connectors and mounting bolts.
- Carefully unplug all electrical connectors and remove retaining clips. Note connector positions or take photos to aid reassembly.
- Unbolt the unit and transfer any required relays, brackets or grounding straps to the replacement unit if necessary.
- Fit the BSM, reconnect connectors and secure all fasteners. Reconnect the battery and verify all affected systems (lights, starting, engine management, etc.).
- After installation, check fuses and relays and perform a full functional test of vehicle electrical systems.
Installation Recommendations
- Always disconnect the battery before removal and installation.
- Handle connectors and pins carefully to avoid bending or corrosion damage.
- If the unit requires transfer of relays or mounting hardware, ensure they are fitted exactly as on the original unit.
- Use dielectric grease on exposed terminals where appropriate to reduce future corrosion risk.
- If any fault persists after replacement, inspect wiring harness and grounds for damage or corrosion.
Why This Part Most Often Fails
Common failure causes include water ingress and corrosion of contacts, heat-related degradation of internal components, vibration damage to solder joints, and connector corrosion. Plastic mounting tabs can be broken during vehicle servicing or removal, which usually does not affect electrical function but may affect secure mounting. Vehicles exposed to moisture, road salt or lacking proper engine bay seals are at higher risk of BSM faults.
Note: This is a used unit offered with a guarantee of functionality. Ensure correct product code match (9644038780 / 6500Y1) for proper fitment before installation.
