FAW Multifunctional Antenna Logic Assembly: The 3 Essential MSUs for Total Connectivity

Welcome to this essential technical guide on the FAW Multifunctional Antenna Logic Assembly. This component is the primary communication hub for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. It serves as the vehicle’s “ears,” receiving and transmitting critical data and broadcast signals, including AM/FM radio, GPS/BDS navigation, and 4G/LTE telematics for fleet management.

The “Logic Assembly” designation is key. This is not a simple, single-function antenna. The FAW Multifunctional Antenna Logic Assembly (P/N 7903010-61B) is a sophisticated, co-located system that houses multiple, independent antenna elements within a single, aerodynamic, and waterproof housing. This “logic” of integration is critical for modern vehicle design, reducing drilling, simplifying cable runs, and protecting sensitive electronics from the elements.

This in-depth guide is a crucial resource for technicians and parts specialists. We will deconstruct the entire FAW Multifunctional Antenna Logic Assembly into its three primary Minimum Serviceable Units (MSUs): the main ‘Multifunctional antenna assy’ itself, the specialized ‘Harness fixing tape’ (3724152-61B) used to secure its delicate cables, and the single ‘Cross recessed pan head screw’ (Q2140628) that provides its critical ground-plane connection.

MSU 1: The “Black Box” Logic of the Antenna (7903010-61B)

This component, the ‘Multifunctional antenna assy’ (7903010-61B), is the “longer” and most complex part of the assembly. It is the primary MSU and functions as a sealed “black box.” It is not field-serviceable; if any one of its internal functions fails, the entire unit is replaced.

The core “logic” of this assembly is the co-location of three (or more) separate antenna systems within one housing. Each system has its own dedicated internal antenna element and its own coaxial pigtail cable.

1. Function 1 Logic: AM/FM Radio

This is the most traditional function. The FAW Multifunctional Antenna Logic Assembly contains a passive or active (amplified) element, such as a spiral-wound mast or internal coil, designed to receive broadcast radio frequencies (530-1700 kHz for AM, 87.5-108 MHz for FM). This signal is sent via a dedicated coaxial cable to the vehicle’s main infotainment/radio head unit.

2. Function 2 Logic: GPS/BDS (Navigation)

This is the most critical function for modern logistics. The assembly houses a specialized “patch antenna,” typically a square of ceramic, that is precisely tuned to receive very low-power signals from Global Navigation Satellite Systems (GNSS), including American GPS and Chinese Beidou (BDS).

This data is absolutely essential for the FAW Multifunctional Antenna Logic Assembly to perform its job. This satellite data feeds multiple downstream systems:

• The ‘Tachograph’ (7914010-61B): For legally required, tamper-proof tracking of vehicle speed and location.
• The ‘Vehicle information service terminal’ (7913010A54W-000): For on-board navigation and route-planning.
• The Fleet Management System: For real-time location tracking by the home office.

3. Function 3 Logic: 4G/LTE/GPRS (Telematics)

This antenna element is the truck’s “internet” connection. It is a cellular antenna that allows the on-board telematics modules (like the ‘Fleet management module’ 7925070-91W-C00 and the ‘4G antenna assy’ 7903060-95T) to transmit and receive data over the mobile phone network.

This “logic” is the key to the connected fleet. It allows the truck to send real-time engine fault codes (DTCs), driver logs, and fuel economy data back to headquarters, while also receiving new dispatch orders, route updates, and software patches. The FAW Multifunctional Antenna Logic Assembly is the single gateway for all this data.

Construction and Serviceability

The housing is made of UV-stable, impact-resistant ABS polymer. The most critical component is the high-density foam or rubber gasket on its base. This gasket provides a waterproof seal against the truck’s metal roof, preventing water leaks that can destroy the cab’s headliner and cause rust. Failure of this gasket is as critical as an electronic failure. As an MSU, the entire unit is replaced if any one of its three functions fails.

Core 2: The Fastening & Securing Logic (MSUs 2 & 3)

This final group of MSUs covers the installation hardware for the FAW Multifunctional Antenna Logic Assembly. While they seem simple, they are critical to the system’s performance and longevity.

1. The Screw (MSU 3): ‘Cross recessed pan head screw’ (Q2140628)

The parts list calls for one (1) of these screws. This indicates it is the main mounting stud that passes through the roof and is secured from inside the cab. This screw’s “logic” is twofold:

• Clamping Force: It provides the pressure needed to compress the base gasket, creating the watertight seal.
• Ground Plane: This screw creates the primary electrical ground for the antenna system. Many antennas (especially AM/FM) use the large, flat metal roof of the cab as a “ground plane,” which is an active part of the antenna system itself. A loose or corroded screw here will destroy radio reception and can impair GPS/4G performance.

2. The Tapes (MSU 2): ‘Harness fixing tape’ (3724152-61B)

The list specifies four (4) of these “tapes,” which are essentially specialized, high-strength cable ties. The “logic” of including these in the FAW Multifunctional Antenna Logic Assembly parts list is critical: cable management.

The pigtail cables coming from the antenna are delicate, high-frequency coaxial cables. They cannot be pinched, kinked, or allowed to vibrate (chafe) against a sharp metal edge. Doing so will damage the internal shielding and ruin the signal. These four tapes are the OEM-specified MSUs used to secure this cable run from the roof, down the A-pillar, and to the dashboard. Using a standard, cheap zip tie could pinch the cable or break over time. These are a tiny but essential MSU for a reliable installation.

FAW Multifunctional Antenna Logic Assembly Parts List

The following table provides the complete, detailed breakdown of all 3 component types identified in the FAW Multifunctional Antenna Logic Assembly diagram for the FAW CA4251P66K24T1A3E5 tractor.

Technical Specifications and Assembly Context

The specifications for the FAW Multifunctional Antenna Logic Assembly are defined by its function as a multi-band receiver and transmitter for the vehicle’s core communication, navigation, and telematics systems.