I've replaced the OEM radio with an aftermarket stereo head unit and I have no reception at all! I've wired everything correctly using an adapter for the original radio and the antenna. At wits end. I've spoken with a really reliable installer but still no reception. I looked for the antenna amp but can't find one (drivers side rear pillar) any and all advice welcome!
Curious. I also have no radio reception in my aftermarket unit even though I know it's all hooked up right. Hasn't bothered me too much since I just bluetooth connect to my phone, but I'd like it to work properly.
After a whole lot investigation I found that one of the previous owners had removed the antenna amplifier and hand spliced a cheap antenna to the antenna line that feeds the radio. These can also fail over time. The location of the antenna amp is in the drivers side rear wheel behind the covering (318ti hatchback) Also check wiring and loose pins in the connector to the radio. Typically white. I'm replacing the entire antenna amp.
After Market radio-No reception 
Linear Mode
