Amplifier Won't Turn On

Step 1: Check remote turn-on wire Voltage at amplifier remote terminal when head unit on? Should be 12V. If 0V: head unit not outputting remote, or wire broken.

Step 2: Check power wire Voltage at amplifier B+ terminal? Should be 12–14.4V. If 0V: blown fuse, broken wire.

Step 3: Check ground Resistance from amplifier chassis to battery negative? Should be < 0.1Ω. If high: fix ground.

Step 4: Check fuse Inspect main fuse and any in-line fuses. Visual inspection not always reliable — use continuity test.

Step 5: Minimum voltage protection Some amplifiers have low-voltage protection below 10–11V. If battery is weak or discharged: amplifier won't start. Charge battery.