A common complaint on later model BMWs (those with the amplified “diversity” antenna systems using the rear window defroster grid, as well as “shark-fins”) is poor radio reception. This problem can show itself on both the FM and AM bands and is typically progressive. The cure is relatively easy to implement. Check the steps below, shown on a 4-dr E46 model (3-series 99-05). Other models will be similar. The applicable Bentley repair manuals will detail the C-Pillar trim panel removal on other BMW models.
Other DeoxIT products:
Non-Marring pry tools:
2) Use a non-marring pry tool to pry the C-pillar trim cover loose. There are two clips at the upper end of the cover (see the following photos). Unplug the light harness plug and then pull the cover upward to fully remove it.
4) Unplug and remove the window grid connector harness.
6) Reassemble the window connector harness and the output and power plugs. Reinstall the C-pillar and the door gasket.