High-to-low wiring harness, subwoofer wiring harness 1. Compatible models: Buick, GM, GMC, Chevrolet 2. Function: To achieve the conversion of the original car's high-level audio signal to a low level, and provide an adaptation signal for the subwoofer and amplifier 3. The wiring harness is clear for quick identification 4. The transparent protective shell covers the key circuits for easy inspection