[BAKX3]

I just got a 2007 X3 and have come to the conclusion that the easiest (and cheapest) way for me to get what I want is to install the new Alpine 148BT head unit with the factory amplifier. 3 significant issues I have encountered and do not know how to easily overcome are;

1) Speaker output level - the Metra wiring kit for other BMW's either specifies a level converter OR converts the factory wires from the amp to RCA's for plug-in to the pre-outs of the radio. the Metra kit for the 2007 X3 is a straight hook-up off of the Alpine's speaker level outputs to the amp. Question; does this work, or is it problematic.

2) Backup sensors - I have become aware that in installing an aftermarket stereo to other BMW models, the back-up sensor's beeping is lost. Will this happen to me and is there a fix?

3) Steering wheel controls - I purchased a Metra Axxess ASWC-1 universal unit, but upon inspection and reading the directions, think it is a Mickey-mouse solution at best. Anyone have experience with these, or a better remedy?

Is there anything else that I am not aware of and will have to deal with? People on forums have mentioned slow power drain issues (true/untrue)?

Thanks in advance - any help is appreciated!
Scott

[joylove]

1) Drive the amp from speaker level audio. The wires are twisted pair and most suited to the balanced high voltage speaker level outputs. Purists will whine about the extra noise from the amp in the HU. The 10dB noise rise from the addition gain stage will be utterly swamped by the 70dB of road and wind noise. Saturation is another issue, however you are not going to be able to get the same amount of gain in the system with a line level to speaker level balun so you will lose 20-25dB of gain and hence SNR in the pursuit of maximum volume and it's a backwards step. The amp input impedance will be high so saturation will come later than if it were driving 4R nominal.

2) this only affects the MOST bus cars. E83 uses a separate gong for PDC.

3) The steering wheel controls are messages sent over the iBus, a 1 wire bus connecting many many modules to allow them to chat. The iBus carries a lot of chatter about many things, temperatures, speed, rain readings, light readings, door and window positions, ignition state, MFSW commands etc.

To extract the MFSW button commands with a "universal" SWC such as the PAC-SW for some reason it is necessary to "learn" each message to each headunit function. These messages haven't changes from 1993-2009 so I don't know why they don't come pre-coded to the SWC but I digress. So it becomes necessary to disconnect the iBus from the vehicle at the MFSW and perform any learning with only the MFSW module on the iBus; lest you learn VOL+ to something like the gear shift position P or the engine speed 0 RPM.

Power drain issues might present if you hook the SWC to the permanent live.

One other thing is the iBus idles at 12V and the iBus master (the instrument cluster and as a backup the lamp switch) pulls this high for idle. Every module pulls it low to signal a logic 1. The module will go to sleep after 30s of iBus inactivity. After a few more minutes (16 or 30 IIRC) the bus falls to 0V and everyone goes to deep battery-saving sleep.

The MFSW and SWC must then work together to replicate this behavior to prevent excess current drain or the MFSW going to sleep after 30s periods of inactivity. Consider reconnecting the MFSW to the iBus after the learning process is complete if you experience undesired sleep behaviour.

[BAKX3]

I am going to use the Metra Axxess ASWC-1... an installer in CA that has installed in X3's says there will be no problems with ibus communication/mapping and/or the sleep mode issue.
You seem to really know what you are talking about (mechanically) and I very much appreciate the information. What are you thoughts on the above?

[joylove]

I don't know the Metra Axxess ASWC-1 but I just googled the pdf instructions and no wiring adjustments need to be made to teh vehicle harness and it seems to auto detect so it should be good.

[BAKX3]

I just got the Alpine head unit and Metra Axxess installed in my 2007 X3. Your advice and knowledge came in very handy in giving me the confidence to go ahead and do the install.

All was going well and according to plan until we went for a test drive. 2 lights are now lit on in the gauge cluster. The BRAKE light is lit yellow and the "4x4 with an exclamation point and circular arrow around it" is also lit yellow. I consulted the owners manual and found that the second light is the DSC light and hitting the DSC button does not turn it off as it should. Manual says that when the DSC and BRAKE are lit yellow in conjunction with each other, it means that the DSC is malfunctioning and could cause problems with the drive train. Not sure if this is a problem related to tapping into the ibus, or if it is a real problem with the DSC...too much coincidence that it is timed with the radio install.

Please help...Thanks in advance,
Scott

[joylove]

Is all of the aftermarket equipment working? Consider reverting to stock as a test. If the iBus is in trouble things go weird, like the winkers, dash lighting, memory seats.

For me, when I changed the battery I got a load of lights up on the dash. I needed to steer from one lock to the other and do some parking lot-driving. I guess they forget their calibration without power.

[BAKX3]

Yes, everything is working properly (AlpineCDE HD149BT, Metra Axxess ASWC-1). All of my connection were soldered and heat-shrinked. All connections were triple checked. I used a Metra dash kit and a Sosche harness adapter (which had all of the pin-outs wired as opposed to the Metra harness which didn't have a switched power or ibus connection).

Upon connection the battery and firing the system up, the ASWC did not recognize (as diagnosed by the flashing light sequence). I had to reset the ASWC and let it recognize a second time. Second time worked like a charm.

I do not know at what point the DSC and BRAKE lights came on.

I will try to drive in a parking lot or a short drive, lock to lock the wheel and actuate as many controls as possible to see what happens. If that does not work, I will try disconnecting first the ASWC and next the Alpine and see what happens. If that fails, with the above still disconnected, I will disconnect then re-connect the battery...If all of the above fails, what would you do next? Take it to a repair shop or dealership?

[joylove]

First if the vehicle harness is not damaged, consider reverting to stock, if only temporarily. Often the issue become apparent during or immediately after.

Next consider a fault reader, they are more useful than a multimeter. This one is BMW specific and covers more than gust the engine and gearbox. Note it probably doesn't support a 2007+ N52 engine.

http://www.ebay.com/itm/H112-Creator...983b59&vxp=mtr