Description
Product Overview
The BSM B4 Siemens (Part Number 9643498780) is a vehicle engine-bay control module used on a range of PSA Group cars. This used unit is supplied with a guarantee of functional operation. It serves as a central power distribution and control module for several engine-bay electrical circuits, relays and fuses, and is commonly replaced when drivers experience electrical faults or intermittent system failures.
Compatibility
- Citroen: C2, C3, Berlingo, Xsara, Xsara Picasso
- Peugeot: 206, 307, 406, Partner
Function And Common Faults
The BSM (engine-bay service box) controls and distributes power to multiple components via fuses and relays. When it degrades or suffers water ingress, corrosion or connector damage, symptoms can include blown fuses, intermittent electrical functions, warning lights, or failure to start. Heat and long-term vibration also accelerate wear of internal contacts and connectors.
Replacement & Installation Notes
Replacement is straightforward for experienced technicians and DIYers with basic tools. Recommended steps:
- Disconnect the negative battery terminal before starting to avoid short circuits.
- Locate the BSM in the engine bay (usually near the battery or inner wing) and remove any protective covers.
- Carefully unplug electrical connectors and release retaining clips. Note connector positions to avoid miswiring.
- Remove mounting screws or bolts and replace the module with the new unit.
- Reconnect all connectors, reattach covers, reconnect the battery, then start the vehicle and verify all electrical systems and fuses.
Inspect wiring and connector seals during replacement. If corrosion is present on connectors or ground points, clean and protect them to prevent recurring faults.
Condition And Warranty
This item is a used part offered with a functional guarantee. Cosmetic wear and possible damage to some mounting tabs may be present; such damage typically does not affect operational performance. The unit is supplied to provide a cost-effective and reliable replacement option for repairs and maintenance.
Technical Information
- Manufacturer: Siemens
- Model: BSM B4
- Product Codes: 9643498780, 9643498780-00, T118470004 K, S118470004 E, 6500Y3, 6500Y1
- Other Numbers: 6500Y3, 6500Y1
Why Choose This Part
For mechanics and DIY enthusiasts repairing Citroen or Peugeot vehicles, the BSM B4 Siemens unit represents a practical and economical solution where original equipment functionality is required. It restores reliable power distribution and can resolve a range of electrical issues when fitted correctly.
