Description
BSM B3 Delphi control unit for Citroën and Peugeot vehicles. This is a used part with a warranty of functionality. Some mounting brackets may be damaged – this does not affect functionality.
Product Overview
The BSM B3 (Body System Module) by Delphi is a vehicle body control unit used on a range of Citroën and Peugeot models. It centralizes and manages several comfort and electrical distribution functions such as central locking, interior lighting circuits, relay/fuse switching and other body-related electrical functions. This replacement unit is a practical option for professional workshops and skilled DIY mechanics looking to restore lost functions caused by a faulty BSM.
This part is commonly searched by its product numbers, so make sure to check references: 9650664080, 6500Y1, 6500Y3. Because this is a used unit supplied with a functionality warranty, cosmetic damage to plastic mounting brackets does not affect electrical performance.
Technical Information
- Manufacturer: Delphi
- Model: Citroën C8; Peugeot 307, Peugeot 406; Peugeot 807
- Product Codes: 9650664080, 6500Y1, 6500Y3
- Additional Numbers: BSM B3
How To Replace
Replacement of a body system module should be performed by a professional or an experienced DIY mechanic. Typical replacement steps:
- Disconnect the vehicle battery before any work to avoid short circuits and protect the unit.
- Locate the BSM—usually mounted behind trim or fuse panels in the passenger compartment on affected Citroën/Peugeot models.
- Remove any trim panels and unscrew the unit from its brackets. Inspect connectors and wiring for corrosion or damage.
- Carefully unplug electrical connectors (note locking tabs) and remove the faulty unit.
- Fit the replacement BSM, reconnect all connectors and secure the unit to its mounts.
- Reconnect the battery and verify basic functions (locking, lights, indicators). Some functions may require adaptation/coding after installation.
Installation Recommendations
- Always disconnect the battery before starting work and follow manufacturer procedures to avoid damage.
- Check fuses, relays and connector condition before and after replacement; a failing wiring harness or a blown fuse may indicate underlying problems.
- Ensure connectors are fully seated and locking tabs engaged to avoid intermittent faults.
- If multiple functions are affected after replacement, professional diagnostic equipment may be required to adapt or code the module.
- Prefer professional installation when uncertain—this part controls several vehicle electrical circuits.
Most Common Causes Of Failure
- Water ingress or moisture leading to corrosion of pins, connectors or circuit board traces.
- Electrical surges or short circuits caused by faulty wiring, jump-starts or alternator faults.
- Thermal stress and age-related component wear in vehicles with long service life.
- Physical damage to connectors or mounting points from poor installation or impacts—mechanical damage can be cosmetic but wiring damage can cause functional faults.
Choosing a BSM by correct part number significantly increases the chance of direct fit. This unit is suitable for technicians and experienced DIYers restoring electrical and comfort functions on compatible Citroën and Peugeot models.
