// What fails
The SAM (Signal Acquisition Module) on a Mercedes — and the equivalent BCM/body modules on other makes — distributes power and signals to almost everything you touch: lighting, wipers, central locking, windows, fuses and relays. Water ingress is the classic killer, followed by corroded connectors and failed output drivers.
Symptoms are maddening because they look like ten separate faults at once. Replacing the module means coding and matching it to the car; repairing the original board avoids all of that, which is our default approach.
Symptoms we see every week
- Random electrical faults: lights, indicators or wipers with a mind of their own
- Repeated blown fuses on one circuit
- Central locking or windows dead on one side of the car
- Battery drain that flattens the car overnight
- No communication with the SAM/BCM on diagnostics
Our process
- DiagnoseThe fault is confirmed with proper diagnostics and board inspection before any work is quoted.
- RepairComponent-level repair on your original unit — coding, keys and adaptations preserved.
- Bench testThe repaired unit is proven on the bench under realistic conditions before it goes back.
- WarrantyWork is covered by our workshop warranty, with terms confirmed in writing on your quote.
Board-level repair: corroded tracks rebuilt, failed drivers replaced, connectors restored, then every output channel exercised on the bench before the module goes home.
Pricing
SAM and body module faults vary widely, so we quote per unit. Send the part number and a description of what is misbehaving to 07404 487674 and we will price it honestly.
Frequently asked questions
How do I know it is the SAM and not just a fuse or relay?
You often cannot tell from the driver’s seat — that is the point of proper diagnostics. Multiple unrelated faults appearing together, or fuses that keep blowing, point at the module. We confirm before recommending repair.
My SAM got wet — is it saveable?
Often, if it is dealt with quickly. Corrosion spreads, so disconnect the battery and get the module to us as soon as you can. We rebuild tracks and replace damaged components where the board allows.
Will the repaired module need coding?
No — repairing your original unit keeps all coding and configuration intact. That is the main advantage over a second-hand or new replacement.
Do you repair body modules on non-Mercedes cars?
Yes. The same board-level skills apply to BCMs and fuse-box modules across most makes. Send the part number and we will confirm whether yours is one we can take on.