A06-75984-003 | Genuine Freightliner® Electronic Chassis Control Module

1. Primary Brand Compatibility

This module is engineered exclusively for heavy-duty commercial vehicles manufactured under the Daimler Truck North America (DTNA) umbrella:

• Freightliner Trucks

• Western Star Trucks (on shared platform chassis)

2. Common Truck Models & Fitment

The A06-75984-005 module is most commonly utilized in Freightliner’s modern multiplexed electrical architectures (often linked to the Bulkhead Module or Cabin Control systems). It primarily fits Class 8 highway and vocational models:

• Freightliner Cascadia (specifically compatible with select model years within the Cascadia platform depending on the vehicle's electrical spec sheet).

• Freightliner M2 106 & M2 112 (Medium-duty vocational trucks).

• Freightliner Coronado / 122SD (Severe-duty vocational models).

Programming Note: This electronic chassis control module is a vin-specific, programmable computer. After installation, it typically requires flashing or programming using Daimler’s proprietary diagnostic software (DiagnosticLink®) to configure the multiplexing parameters to match your truck's specific build sheet.

1. What is it?

In modern Class 8 Freightliner trucks (like the Cascadia), the electrical system does not use traditional direct-wire fuses for every single component. Instead, it relies on a multiplexed computer network. The SAM Chassis acts as a localized "smart" power distribution and control hub.

It is mounted on the cabin's firewall (usually accessible from the engine side) and handles electrical distribution for everything located from the cab back to the rear of the truck frame.

2. Core Functions & Responsibilities

• Exterior Lighting Control: Directly manages and distributes power to the rear taillights, brake lights, turn signals, and license plate lights.

• Trailer Interface Management: Houses the relays and fuses that supply power to the trailer connector plug (including trailer auxiliary power, tail lights, and trailer ABS).

• Fuel and Drivetrain Heating: Manages power routing to the fuel-water separator heaters, fuel line heaters, and specific transmission electronics.

• Smart Fuse Protection: Features integrated solid-state circuit breakers, relays, and traditional fuses that communicate with the vehicle's central computer (the Bulkhead Module/SAM Cabin) over a J1939 CAN-bus network to monitor for short circuits.

1. Total or Partial Failure of Trailer Lights

Since the SAM Chassis manages the power outputs to the trailer cord, a failing module will often cut power to the trailer. You may lose trailer running lights, brake lights, turn signals, or trailer ABS power, even though the truck’s cabin lights and headlights work perfectly.

2. Rear Truck Lights Staying On or Not Working at All

Multiplex systems use solid-state switches inside the module. When these internal drivers fail, they often lock "on" or "off." You might notice that your tractor's rear tail lights or brake lights refuse to turn off (draining the batteries overnight) or will not illuminate at all despite installing new bulbs.

3. Intermittent "No-Start" or Fuel Heater Faults

The SAM Chassis controls power to the fuel-water separator heater and communicates with various chassis sensors. If the module has internal corrosion, it can disrupt the CAN-bus communication network, causing the engine control module (ECM) to throw communication codes, occasionally resulting in a crank/no-start condition.

4. "ECU 143" or "SAM Chassis" Dashboard Fault Codes

Modern Freightliner trucks will display diagnostic fault codes directly on the dashboard screen. If you see active faults indicating loss of communication with Source Address 216 (SAM Chassis) or active SPN/FMI codes linked to the chassis module, the ECU is struggling to send or receive data.

5. Corrosion and Water Intrusion in the Plug Connectors

Because this module is located on the firewall under the hood, it is highly exposed to moisture. If you unplug the large harness connectors on the A06-75984-005 and find green corrosion on the metal pins, water has breached the seals. This corrosion bridges electrical paths, causing random fuses to blow and components to activate on their own.