Hope someone can point me in the right direction. Have 2011 335is. It has aftermarket amps. Has worked flawlessly for 3 years. One day radio stopped playing and screen went blank. Thought it was the cic head unit so replaced it and screen started working but radio did not. Thought it may need coding to work. Dealership tried several times but says it will not take a code. Probably because radio doesn't come on. No power on light next to on off button. No remote turn on power making it to amps. Thought it was corroded through firewall battery terminals interfering with power signal but check and they are good. Anyone have an idea what could be causing the failure of radio to come on and preventing ability to be coded?