• Most of the time when there is no sound (or the system is not turning on) it is due to the remote/switched wire connection (Orange wire on ST200 Classic, Blue/White wire on the ST600 Cruiser and Solid Blue wire on the ST900 Platinum). To confirm the system works you can connect this remote/switched wire directly to battery positive and the system should turn on. If so, then check that your switched power source connection is connected properly per the instruction manual (this is a source that comes on and off with the bike).• Also check that the Positive (+) and Negative (-) wires are securely connected to the battery. These 2 wires and the above mentioned remote/switched wire must all be properly connected for the system to work, even if the amplifier appears to turn on.• Check that the wires are not cut, melted or have any bare wire between the amp and speakers, battery or switched wire.• Check that the fuse is still good, even if the amp light(s) still turn on.ST900 PLATINUM EDITION SYSTEM: If everything is connected and powering on but you have no sound, please check that the 3.5mm (headphone jack) to RCA cable is connected properly.  The RCA end should connect to the input side of the amplifier and the 3.5mm (headphone jack) side should connect to the female 3.5mm (heapdhone jack) plug on the MTX Bluetooth handlebar controller.