Dongfeng KL truck spare parts right SMJ box 3724421-C3300

Built as a central hub for right-side electrical signals, this SMJ box integrates signal distribution, conversion, and protection functions for critical truck systems. It manages inputs/outputs from the right headlight (OE 3730010-C3300), side marker light (OE 3730030-C3300), door switch, and rearview mirror adjustment motor—reducing wiring complexity by 40% compared to discrete junction points. The internal PCB (printed circuit board) uses gold-plated traces (conductivity ≥98% IACS) for stable signal transmission, with a signal-to-noise ratio (SNR) of ≥90dB to prevent interference. It converts analog signals from sensors (e.g., door position) to digital data for the BCM, ensuring real-time status feedback. A built-in signal prioritization module ensures critical functions (e.g., brake lights) take precedence, avoiding signal congestion during high-load operation

Engineered to protect electrical components from chassis harshness, the 3724421-C3300 SMJ box features a robust enclosure design. The outer shell is made of flame-retardant ABS+PC alloy (UL94 V-0 grade) with a 3mm wall thickness, achieving impact resistance of 10kJ/m²—capable of withstanding accidental collisions with tools or cargo. A foam gasket (EPDM material) between the cover and base enhances the IP67 rating, blocking water and dust ingress even in rainy or dusty construction environments. The internal PCB is coated with conformal silicone (100μm thickness) that resists moisture, corrosion, and vibration (10-500Hz), preventing short circuits caused by environmental factors. Reinforced mounting lugs (4-point design) distribute stress evenly, avoiding enclosure deformation that damages terminals

Optimized for maximum electrical safety, the SMJ box integrates multiple protective mechanisms to safeguard the truck’s electrical system. Each terminal circuit is equipped with a miniaturized circuit breaker (5-15A rating) that automatically trips to cut off power in case of overcurrent or short circuit, avoiding wire overheating and fire risks. A reverse polarity protection diode prevents damage from incorrect harness connection—a common issue during maintenance that costs $300+ to repair. The PCB’s overvoltage protection (16V max) shields sensitive components from voltage spikes caused by alternator fluctuations. A thermal fuse (120℃ activation) provides secondary protection, ensuring the box remains safe even if primary breakers fail. These features comply with ISO 26262 functional safety standards for automotive electrical systems

This right SMJ box is designed for convenience and long-term cost savings for Dongfeng KL operators. The transparent cover allows visual inspection of terminal connections and circuit breakers without disassembly, reducing diagnostic time by 60%. Color-coded terminals and labeled connectors (e.g., “Right Headlight,” “Mirror Motor”) simplify harness connection, minimizing installation errors by 90%. The OE-compatible design ensures perfect integration with the BCM, avoiding the electrical malfunctions (e.g., light failure, door sensor errors) of aftermarket boxes that lead to regulatory fines ($200+ per violation). The high-durability enclosure and components extend service life to ≥300,000km—three times that of non-OE alternatives. Backed by a 2-year/200,000km Dongfeng warranty, it provides reliable signal management and predictable maintenance expenses, enhancing fleet efficiency and reducing downtime