3 Series (E46) 1997-2006
Standard
The standard audio system has a factory tape or CD radio. Some older models also have a small text based navigation display. The general rule with these systems is tape players use the a 17 way round pin connector, while CD players use a quadlock connector. However, this isn't always the way so would recommend removing the factory radio and checking which plug is used.
Standard with Harman Kardon
Some vehicles with the standard radio will also have a Harman Kardon amplifier. This can be identified by the badge on front tweeter housing. These amplifiers are turned on by a 12v switch signal sent from the factory radio and send audio as a low level (pre amplified) signal. Fitting an aftermarket headunit or handsfree kit will require high to low level adapters.
Navigation Screen
Vehicles with factory navigation screens have the radio tuner module in the rear of the car, behind a panel in the left hand side of the boot. There are two types of tuners, one has the 17 way round pin connector while the other has the 40 way Quadlock connector. It is a 10-15 minute job to remove the panel in the boot, locate the tuner and identify which type plug is in the car.
Navigation with Harman Kardon
There are vehicles with factory navigation and Harman Kardon amplifiers. Connections can be made by running extensions to the tuner as in the non-Harman Kardon navigation system. However speakers will need to be rewired and the amp bypassed to output any audio.
Select the factory radio to confirm the correct fitting solutions.
