Adapt and Upgrade Navigation C23 / C43 to BM53 and Cassette Radio Tuner

BMW first introduced their On Board Navigation System in 1995 for the E38 7-Series. The first gen radio tuner uses round pin harness. In 2000 BMW had improved the design. The newer version radio tuner (BM53/BM54) can be adapted to fit and work with the older model GPS navigation systems using a few simple adapter harnesses outlined below. 

These adapters will also allow E46 3-series, E39 5-Series and E53 X5 owners to install replace the older cassette radio with an updated in-dash Business CD (CD53). 

 

BMW P/n. 61.12-6 913 957 (no longer available) Round Pin to Flat Pin Main Radio Antenna Adapter
This is the main harness plug for your radio. Your car's original radio has a main plug (with round pins) and two 10-pin audio input cables that integrate with the main harness plug. The new Sirius-ready radio you have has a flat-pin main harness with two 12-pin audio input plugs that integrte with the new main harness.

BMW P/n. 61.12-6 924 785 - 10-pin to 12-pin radio audio input adapter
This converts the original 10-pin audio input plugs for your original radio into the 12-pin plugs that the new radio expects. I actually modified this plug for my car significantly by removing one of the 10-pin plugs, and you may too, as the one of the two 10-pin plugs is for the CD changer, but your car would not have had that plug at all.

BMW P/n. 61.12-6 913 955 - New Gen Radio Antenna Adapter
Your car's original radio has two antenna inputs, and neither is similar to the new gen radio's antenna plug. Furthermore, the new gen radio only needs a single antenna input. This will convert the larger of the two antenna plugs into the style that fits your Sirius-ready radio.