After the usual HK amp failure I decided to go aftermarket and replace the HU. I've rewired the speakers and everything sounds great. Problem is I have virtually no radio reception. I only get two or three FM stations and no AM at all. Car is an 04 R53 with Nav. I did use the FM antenna converter so that I didn't have to cut any wires. There were several wires on the OEM HU that went unused in the new install. Were these antenna power? Any help would be appreciated!

 

Antenna amplifier is activated by 12V DC sent up the coax from the OEM radio. You can buy an adaptor.