Use BMW Cd player to replace a BM24/BM54?

big bob · #1 03-10-2010, 09:22 AM

With used prices on BM24/BM54 being so high, has anyone considered using a late model BMW CD player as a replacement? The tuner box has basically the same functions for nav audio and Aux audio, only TMC would possibly be missing.

Any thoughts?

Brian-bmw · #2 03-10-2010, 10:07 AM

An in-dash radio module will not work in a navigation-equipped car. The in-dash radio does not know to subordinate itself and communicate with the nav computer. It assumes that it is the center of car's audio system.

big bob · #3 03-10-2010, 10:15 AM

Interesting. I thought the tuner/amp simply took commands for volume, tuning and source over the ibus, whether from the steering wheel or the nav screen. The screen then also sends commands to the nav computer regarding navigation stuff over the dedicated nav bus.

Can you tell me a little more about what you know please?

ccfj1 · #4 03-10-2010, 10:20 AM

Interesting, I don't think that a "normal" radio can be used as the front has all the buttons and knobs, the MFSW **may** only work the volume and switch channels etc, not sure about the rest.

Be pretty cool to try though

Brian-bmw · #5 03-10-2010, 11:01 AM

Yes, that is part of it. The radio (all versions) accept volume, tuning, source, balance, fader, etc. commands over the I-Bus. The major difference is presentation. The in-dash radio assumes it is the center of the presentation universe along with the MID. So, it does not know to send the appropriate graphical presentation signals to the nav computer. So, an in-dash radio might work, but the radio nav screen would likely be dark.

big bob · #6 03-10-2010, 11:15 AM

That information such as the FM frequency and track info must be on the iBus, for highline dash and MID equipped cars.

The NAV computer may get that data from the nav bus pin X18805.3. If the business CD radio has this pin it could work!

Brian-bmw · #7 03-10-2010, 11:22 AM

Yes, all that is on the I-Bus. The key is that I-Bus communicaions is not general broadcast. Instructions are directed to specific devices. So, most likely, the in-dash radio is not directing anything to the nav computer. Others have tried it, and it did not work. The best I can say is give it a try and see what happens.

big bob · #8 03-10-2010, 11:28 AM

Thanks. Usefull info. Repp'd.

zeronoo · #9 02-01-2011, 09:07 AM

@Brian-bmw: you a right, but what about using in-dash radio with navigation unit (monochrome type)?...this unit can comunicate for sure with navigation computer...also have aux in, tel in, so is better then bm24

regards

big bob · #10 02-01-2011, 12:54 PM

Quote:

Originally Posted by zeronoo

@Brian-bmw: you a right, but what about using in-dash radio with navigation unit (monochrome type)?...this unit can comunicate for sure with navigation computer...also have aux in, tel in, so is better then bm24

regards

Only some units have the 17 pin connector. Later models have the smaller white and blue plugs used on the LCD monitors. The only problem is that the Business nav has an LCD with menu options that do not match the layout of the BM24. So for example five clicks of the knob right and enter might take you to FM mode on the radio, but also into the entering your destination on the GPS. So you end up programming a route to 1 Apple Street, Aberdeen while trying to tune the radio to Radio 2.

I happen to have all these parts at home so will give it a try to see what happens.