read the unit manual here - Brash Imports

TroubleshootingGeneral problemsSymptomsThe unit cannot bepowered on.Remote controller doesnot work.No sound comes out orit's hard to hear.Poor sound quality orsound distortion.User preset information islost when ACC is off.CausesThe fuse of the unit has been broken.The fuse of car battery has been broken.False operations and etc.Battery has been exhausted.Battery is not installed correctly.Audio output connection is not correct.The volume level is set to the minimum level.The speakers have been damagedl.The audio channel outputs are not balanced.The speaker cord is contacted with thebodywork.Piraticdiscisused.The speakers power rating does not fit intothe unit output power.The speakers are connected incorrectly.,The speaker cord is contacted with thebodywork.ACC and BATT are connected incorrectly.25RemediesInstall a new fuse with correct rating.Install a new fuse with correct rating.Reset the unit.Change the battery.Install the battery correctly.Correct the connection according to(ElectricalConnections Overall Diagram).Adjust the volume to the optimum level.Check the speakers.Adjust the balance of audio channel outputs. Pleaserefer to (Audio control).Use insulating cord for connection.Use original copy disc.Change the speakers.Correct the connection according to(ElectricalConnections Overall Diagram).Use insulating cord for connection.Correct the connection according to(ElectricalConnections Overall Diagram).