Radio will not turn on (no sound/lights)
Possible Cause: Yellow wire (12v Constant) is not connected or incorrect voltage
Action: With a meter, check the connections on the Yellow wire, it should be at least 12volts
Possible Cause: Red wire (12v Ignition Switched) not connected or incorrect voltage
Action: with a meter, check the connection on the red wire for 12v whilst the key/switch is on.
Possible Cause: Black wire (ground) not connected
Action: Be sure the black wire is at a clean metal surface or known ground