Fuse Box - Engine Bay

This procedure covers the removal and replacement of the engine bay fuse box (SAM module) on the 2007-2013 Mercedes-Benz S65 AMG with the 6.0L V12 BiTurbo M275 engine.

Warnings

Tools required

Parts

• Engine bay fuse box (SAM module) × 1 — Use OEM specification
• Fuse box cover seals (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key fob from vehicle
3. Allow engine to cool completely if recently operated
4. Open hood and secure with prop rod
5. Take detailed photos of fuse box and all electrical connections for reference
6. Disconnect battery negative terminal and wait minimum 15 minutes before proceeding

Procedure

1. 1

   Disconnect battery and remove cover
   Remove the battery negative terminal using a 10mm socket. Wait 15 minutes for system capacitors to discharge. Remove the engine cover by pulling upward on the four corners - it is secured by rubber grommets only.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
2. 2

   Remove fuse box cover
   Locate the engine bay fuse box on the left side of the engine bay near the firewall. Release the cover clips by pressing the tabs on both sides and lift the cover away. Remove the cover screws using a T25 Torx driver if present on your model year.
   Torque spec

   Cover Screws15 Nm (11 lb-ft)
3. 3

   Document and remove fuses and relays
   Photograph the exact position of all fuses and relays. Remove all fuses and relays from the fuse box and store them in labeled containers or bags corresponding to their positions. Note that some high-current fuses may require significant force to extract.
   ℹ️High-current fuses (80A+) are press-fit and require firm, even pulling force to avoid bending terminals
4. 4

   Disconnect electrical connectors
   Identify all multi-pin electrical connectors attached to the rear and sides of the fuse box (typically 3-5 large connectors). Press the locking tabs and carefully pull each connector straight out. Mark each connector position with tape and numbering for reinstallation. Some connectors have secondary locks that must be released first.
   ⚠The large brown connector has a sliding secondary lock that must be moved to the unlock position before the main connector can be released
5. 5

   Remove ground connections
   Locate the ground strap(s) attached to the fuse box housing using 10mm bolts. Remove the ground strap bolts and disconnect all ground connections. Clean the contact surfaces with electrical contact cleaner.
   Torque spec

   Ground Strap Bolts12 Nm (9 lb-ft)

   Ground Bolt18 Nm (14 lb-ft)
6. 6

   Remove mounting hardware
   Remove the fuse box mounting bolts using a 13mm socket. There are typically 2-3 mounting bolts securing the fuse box to the bracket on the fender well. Support the fuse box while removing the final bolt to prevent it from falling.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
7. 7

   Extract fuse box assembly
   Carefully maneuver the fuse box out of its mounting location. It may be necessary to tilt or rotate the assembly to clear surrounding components. Be mindful of sharp edges on nearby heat shields and brackets. Inspect the mounting bracket for damage or corrosion.
   ⚠The fuse box may have additional wiring harness clips attached to its underside that must be released before full removal
8. 8

   Transfer components to new fuse box
   If installing a new fuse box, transfer any removable modules, sensors, or brackets from the old unit to the new one. Ensure all module mounting bolts are properly torqued. Do NOT transfer fuses or relays yet.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)

   Mounting Bolts46 Nm (34 lb-ft)
9. 9

   Install new fuse box assembly
   Position the new or serviced fuse box into the mounting bracket, ensuring proper alignment with all mounting holes. Install mounting bolts finger-tight initially, then torque to specification in a cross-pattern.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
10. 10

    Reconnect ground connections
    Reattach all ground straps to the fuse box housing. Ensure contact surfaces are clean and free of corrosion. Apply a thin layer of dielectric grease to prevent future corrosion. Torque ground bolts to specification.
    Torque spec

    Ground Strap Bolts12 Nm (9 lb-ft)

    Ground Bolt18 Nm (14 lb-ft)
11. 11

    Reconnect electrical connectors
    Reconnect all multi-pin electrical connectors to their original positions using your reference photos. Ensure each connector clicks fully into place and that all locking tabs engage properly. Verify secondary locks are in the locked position.
    ⚠Each connector is keyed differently - do not force connectors into incorrect positions as this will damage pins
12. 12

    Install fuses and relays
    Reinstall all fuses and relays to their original positions using your documentation photos. Ensure each fuse and relay is fully seated. High-current fuses should snap firmly into place.
    ℹ️Incorrect fuse placement can cause electrical system damage or component failure
13. 13

    Reconnect battery and program module
    Reconnect the battery negative terminal and torque to specification. The vehicle will require programming/coding of the new SAM module using Mercedes-Benz XENTRY or Star Diagnostic System. This must be performed by a qualified technician with proper diagnostic equipment.
    ⚠️Vehicle will not function properly until SAM module is programmed with VIN-specific data and system configuration
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Reinstall fuse box cover and secure all clips
2. Reinstall engine cover by aligning grommets and pressing down firmly
3. Verify all tools and parts have been removed from engine bay
4. Close hood and ensure proper latching

Verification

• Confirm battery voltage is approximately 12.6V with engine off
• Turn ignition to position 2 and verify all dash warning lights illuminate normally
• Start engine and verify no new warning lights or fault messages appear
• Test operation of all electrical systems: lights, windows, wipers, climate control, infotainment
• Verify no electrical warning messages in instrument cluster
• Perform test drive and confirm all vehicle systems function normally
• Scan for fault codes using diagnostic equipment and verify proper SAM module communication
• Verify all electrical consumers (headlights, HVAC, radio) function correctly

Related trouble codes on this vehicle

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