just check it , the area where it's grounded should be clean and sanded and then the ground applied. also you can get a multimeter put it on dc voltage, touch the ground and a positive see if u get 12 volts or higher. or turn the radio on with a meter on it's positive and negitive and turn the radio up if voltage drops past 12 volts then you have a bad ground or a short. so thats about all you can do. the typical cause is your speakers are to large for the radio to power.
