Mercedes-Benz · Electrical, Sensors & Modules

SAM units (front and rear)

The Signal Acquisition Modules — the front and rear units combining fuse box, relay box and signal processing for most of the car's electrics.

Also called SAM, SAM module, signal acquisition module.

How you know it is this

  • Several unrelated electrical functions failing at once
  • Lights, wipers or windows behaving randomly
  • A car that will not start with no engine fault
  • Water staining or corrosion at the module
  • A battery that flattens overnight from a drain

Worth knowing before you buy

  • THIS IS NOT A FUSE BOX YOU CAN SWAP. The site's own glossary says it: a SAM is coded to the car, and water ingress is the usual reason one dies.
  • The rear SAM is frequently in the boot, under the floor or near a wheel arch, and that is exactly where water collects. Check for a leak before fitting a new one, or the replacement is next.
  • Several odd faults at once is the signature. One odd fault is usually the component itself.
  • Coding required. Repair services exist and are worth pricing on an older car.

What we need to quote it. The chassis number, front or rear, and the fault codes. The chassis number settles the generation, the body and usually the engine in seventeen characters — it is on your mulkiya. A photograph of the old part helps where there is more than one version.

Engine control unitTransmission moduleSAM unitsBody and comfort modulesAirbag moduleImmobiliser and keylessInstrument cluster
Control modules — schematic, to show where the part sits. Arrangement is right; it is a diagram and not a fitment reference.
All electrical, sensors & modules parts
Get in touch

SAM units (front and rear) for your Mercedes-Benz?

Send the chassis number and a photograph of the old part. We come back with genuine, OEM and aftermarket options priced side by side, with lead times.

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