"ON" Circuit Test
- Turn ignition on and connect voltmeter to Lt. Blue-Black wire and ground. Depress and hold "ON" switch in steering wheel. Meter should read 12 volts. If voltage is not available, check horn relay circuit and perform Control Switch Test.
- Release the "ON" switch; 12 volts should remain at the Lt. Blue-Black wire showing that the "ON" circuit is engaged. If voltage drops, check for ground at amplifier, fuse, and/or circuit breaker. Insert a known good amplifier and recheck "ON" circuit if necessary.