FAW Door Controller Logic Assembly: 4 Amazing Components That Secure Your Cab

Welcome to this critical technical analysis of the FAW Door Controller Logic Assembly. This compact but highly intelligent system is the “brain” that governs all access and convenience functions for the doors of the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. It is the central logic hub responsible for interpreting driver commands—from both the internal switches and the external remote control—and translating them into physical actions like locking doors and raising windows.

The “Logic Assembly” designation is crucial. The FAW Door Controller Logic Assembly is not just a simple wiring point. It is a dedicated Electronic Control Unit (ECU), often called a Door Control Unit (DCU). This module (P/N 3746070AA01) is a small computer that communicates with the vehicle’s main Body Control Module (BCM), often via a CAN bus network. It manages the complex logic for power windows (including anti-pinch safety features), central locking, and power mirror adjustments.

This in-depth guide is essential for technicians and parts managers seeking to service this system. We will deconstruct the entire FAW Door Controller Logic Assembly into its four primary components. We will analyze the “brain” itself (the ‘Door controller assy’), the driver’s wireless interface (the ‘Remote control assy’), and the specific, vibration-proof hardware (Q2360620) used to secure this critical system inside the high-vibration environment of the truck’s door.

Core 1: The “Logic” – ‘Door controller assy’ (3746070AA01)

This component is the heart and “brain” of the FAW Door Controller Logic Assembly. Marked as item ‘1’ in the parts diagram, the ‘Door controller assy’ (3746070AA01) is a sophisticated, non-serviceable electronic module that is typically mounted inside the driver’s door shell. It serves as the primary “master” controller for all door-related functions.

This module is the “longer” and more complex part of the system. Its function is to act as a central processing hub, receiving “input” signals and delivering “output” commands.

Input “Logic”: Receiving Commands

The FAW Door Controller Logic Assembly is in a constant “listening” state, waiting for a command from one of several sources:

• Driver’s Switch Panel: It directly receives low-voltage signals from the driver’s window, lock, and mirror switches.
• CAN Bus Network: It “listens” to the vehicle’s CAN bus for commands from the main Body Control Module (BCM). This includes “auto-lock” signals (when the truck exceeds 20 km/h) or “auto-unlock” signals (when the ignition is turned off).
• RF Receiver: It is connected to a receiver that “listens” for the encrypted signal from the ‘Remote control assy’ (3746055-61B).
• Physical Key: It often detects a signal from the physical key lock cylinder, allowing a manual key turn to trigger the central locking.

Output “Logic”: Executing Actions

Once an input is received, the module’s logic executes a physical command by sending 24V power to a specific actuator. This is the primary function of the FAW Door Controller Logic Assembly.

1. Power Lock Actuators: When “Lock” is pressed, the controller sends a brief, timed pulse of 24V power (with a specific polarity) to the door lock motors. When “Unlock” is pressed, it sends a pulse with the *reverse* polarity, driving the motor in the opposite direction.

2. Power Window Motors: This is the most complex “logic.” The controller provides high-amperage 24V power to the window regulator motor. It must be ableto interpret a “short press” for “auto-down” versus a “press and hold” for manual control. Crucially, it manages the anti-pinch safety logic. It constantly monitors the motor’s speed and electrical resistance. If it detects a sudden spike in resistance (e.g., an object is in the window’s path), its logic instantly cuts power and reverses the motor, preventing injury.

3. Power Mirror Motors: The FAW Door Controller Logic Assembly manages the two small motors in each side mirror, providing power for up/down and left/right adjustments.

This module (3746070AA01) is the primary Minimum Serviceable Unit (MSU). If multiple door functions fail simultaneously (and the main cab fuse is good), this controller is the most likely culprit. It is replaced as a single, sealed unit.

Core 2: The Interface – ‘Remote control assy’ (3746055-61B)

This component is the driver’s wireless interface to the FAW Door Controller Logic Assembly. It is the key fob, or “clicker,” that allows for Remote Keyless Entry (RKE).

The “logic” of this device is security. It does not just send a simple “unlock” signal. It is a Radio Frequency (RF) transmitter that sends a unique, encrypted, “rolling code” signal. Each time a button is pressed, the code it transmits changes based on a shared, secret algorithm.

The receiver (either inside the FAW Door Controller Logic Assembly or the BCM) “knows” this algorithm and will only accept the “next” code in the sequence. This “rolling code” logic is a powerful security feature that prevents thieves from capturing and “replaying” your signal to unlock the truck.

The ‘Remote control device diagram’ (3746002-61B) is the associated technical documentation that outlines the “pairing” or “programming” procedure. This is the process a technician must follow to teach the FAW Door Controller Logic Assembly to recognize a new remote.

As an MSU, the ‘Remote control assy’ (3746055-61B) is a high-wear item. The true MSU is its internal battery (e.g., a CR2032 coin cell). When the battery is good but the remote’s buttons are worn out or the internal electronics fail, the entire fob is replaced and the new one is “paired” to the truck.

Core 3: The Fastener – ‘Combination Screw’ (Q2360620)

Marked as item ‘2’, the ‘Cross recessed pan head combination screw’ (Q2360620) is the final component of the FAW Door Controller Logic Assembly. The parts list calls for two (2) of these.

This is not just a standard screw; it is a “combination” (组合) screw. This means it comes from the factory with a captive (non-removable) washer, almost certainly a “spring” or “lock” washer.

The “logic” of this hardware is vibration resistance. A truck door is a high-vibration, high-impact environment (from slamming). A normal screw would quickly vibrate loose. The captive lock washer exerts constant tension on the screw head, preventing it from backing out. This ensures the FAW Door Controller Logic Assembly (3746070AA01) remains rigidly mounted to the inner door panel, protecting its sensitive electronics and wiring connectors from damage.

FAW Door Controller Logic Assembly Parts List

The following table provides the complete, detailed breakdown of all 4 components identified in the FAW Door Controller Logic Assembly diagram for the FAW CA4251P66K24T1A3E5 tractor.

Technical Specifications and Assembly Context

The specifications for the FAW Door Controller Logic Assembly are defined by its role as the “master” electronic control unit for all door-mounted convenience and security systems. This assembly is a key part of the vehicle’s Body Control Module (BCM) network.