BMW C Professional RDS BE1801 Becker BE1940

BMW C Professional RDS BE1801

It was the most expensive system back at the beginning of the 90’s for E31, E32, E34 and E36. What makes it special and different from other BMW head units besides the sound quality is that this 2 component system has control unit with cassette player at the front and the actual radio receiver module at the trunk with double FM tuners.

The 3 letter FM station abbreviations will be displayed on the longer display sorted by the reception strength that one tuner is constantly scanning for and the second tuner is responsible for the currently selected radio station that is displayed on the smaller display (normal in E38 and many modern cars but not back then).

Also it can store 40 FM stations, most of the other BMW radios were limited to ”only” 18 + it has separate tone settings for radio, cassette and CD changer.

Another unique feature is that the radios info can be displayed on the E32/E34 instrument cluster (high). For that the radio connector pins 7(blue/brown/yellow) & 17(white/brown) needs to be connected to the instrument cluster connector X16 pins 23 & 3.

The system consists:

Receiver
Control unit
Shielded connection cable between them
Special radio wiring harness
10 channel 200W amplifier
Different mounting brackets depending on the BMW series.
6 disc CD changer P or A with interface BE1920 or 10 disc CD changer BE0980 with built in interface
Remote control (only for 750iL Highline)

1) Receiver – common issues are faulty FM tuner(s) and malfunctioning main relay (Siemens V23072-C1061-A302). Properly working relay must make loud click when switching on the system.

2) Control unit – common issues are pixel errors that are usually not repairable and faulty tape mechanism.

3) Shielded connection cable

4) Radio wiring harness – Since the receiver is in the trunk there are no speaker wires going to the front radio connector like normally. If you would like to convert this wiring to be suitable for any other BMW radio then you would just need to run 8 new speaker wires to the front radio connector and also extend the antenna cable, no need to replace the complete audio wiring like many are afraid of…

5) 10 channel 200W amplifier – same as used in other BMW 10 speaker hi-fi systems, depending on the year and BMW model the connectors are different.

6) Different mounting brackets depending on the BMW series

7) 6 disc CD changer P (Pioneer PI M941) or A (Alpina AL003E) with interface BE1920 or 10 disc CD changer BE0980 with built in interface. Probably the US and JP market 6 disc CD changers (Pioneer CDX-M91ZBM-02 & CDX-M92ZBM) would also be compatible. The CD changer is connected in series.

8) Remote control for rear seat passengers – this was only available with the Highline option for 750iL.

BMW C Professional RDS remote BE1940

It was an optional extra just for E32 long wheelbase 750iL Highline models. From the 33194 produced 750iL only 1452 were equipped with Highline options (folding tables, refrigerator, remote control for the radio and front passenger seat, rear heated el. seats, dual zone climate control etc.).

Available radio options for Highline:

Becker Mexico CD (BE0879) or Mexico 2000 (BE1460) with remote (BE0940)
BMW C Professional (BE0776) with remote (BE0946)
BMW C Professional RDS (BE1801) with remote (BE1940)
Sony XR-5B925 with remote RM-5B925 (only for Japanese market)

The first 3 are two component systems like Becker used to do back in the early days when they could not yet fit everything inside one body meaning the control unit with cassette/CD drive was at the front and the receiver with amplifiers, audio processing and double FM tuners were located in the trunk.

Becker Mexico CD (BE0879) or Mexico 2000 (BE1460) with remote (BE0940)

BMW C Professional (BE0776) with remote (BE0946)

BMW C Professional RDS (BE1801) with remote (BE1940)

Sony XR-5B925 with remote RM-5B925 – Offered only for Japanese market (FM frequency range between 76 – 90 MHz). Looks like that this remote was also an option without the Highline package. Sony XR-5B127 had also remote but it is hard to find any information so I am not sure if it was also an option for Highline…

Control unit and remote front panel comparison

1) The remote has differently polarized displays meaning they are readable at very low angle and exclusively visible ONLY for rear right seat passenger, control unit displays are only readable when looked more directly.

When using the control unit display in the remote then in normal seating position without leaning over it is quite difficult to see what’s on there (even when the display is set to E31 lower looking angle mode).

*1801 display looked directly (E31 mode)*

2) Control unit display circuit board has small switch behind the cassette door that allows to change the display readability angle between normal and E31 mode, remote is missing that although when control unit display is used on the remote, the switch also functions.

3) The contacts of the control unit display circuit board are longer so when used in the remote they need to be shortened.

4) The face plate is exactly the same used on the control unit just the cassette door and security LED hole are deleted with black covers and the light guide is only for the on/off button.

WHAT IS INSIDE

Test mode

It can be activated from both units although the remote will only perform pixel test, all the other tests and setting region (Europe/US) can be done from the control unit. To enter the test mode switch on the system, press button *️⃣ and right after that simultaneously 8️⃣ & 0️⃣.