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Head Unit Replacement in a 2008 BMW X3 3.0SI

When I’m hunting for vehicles, one of my main evaluations is: what will I change and how difficult will it be to do it? Modern vehicles with integrated systems, diagnostic tools, and “infotainment” systems spell larger expenses and more complexity for even once simple things like replacing head units.

2008 was the last year that BMW offered the X3 without the X-Drive system, which made replacing the factory stereo incredibly straightforward. I left the factory amp in place, just as I did with the head unit in my 1998 328i and my 2006 Z4 Roadster.

From my reading, if you have the factory unit with navigation, you’re going to have a much tougher time going aftermarket. Tough enough that “no nav” was one of my criteria when I was hunting for the right X3 to purchase.

The head unit installation is pretty standard. The only further consideration required in the X3 was retention of the steering wheel controls, which I accomplished by utilizing the ASWC-1 module I’ve used in the past. It’s cheap, reliable, and simple to setup.

parts list

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Single DIN Head Unit, I chose the Pioneer MVH-S501BS, since superceded by the MVH-S512BS ($100).
Scosche BW2337B Dash Kit
Scosche VW03B Wiring Harness ($5, and yes it says for Volkswagen, roll with it)
AXXESS ASWC-1 Steering Wheel Control Module ($50)
Metra 40-EU10 European Antenna Adapter ($7)

removing the old unit

The HVAC vents can be removed with a trim removal tool, credit card, or in my case: bare hands. Pull outward, there are no physical fasteners. There is a climate control cable that is attached to this – as seen in photos, no need to detach, just flip it up and rest it on the dash. The factory head unit is secured by two screws that will be accessible once the vents are removed.

Physically, all you’ll have to do is attach the side “wings” to the head unit you’re installing, then it will secure with a screw on either side. The fit and finish of this dash kit is on par with Metra kits I’ve used in the past. While not a perfect match, the color and finish is pretty close to the Schwarz interior. Much better fit than the equivalent Z4 option from Metra, which is the worst fit I’ve ever seen.

wiring: much easier than it looks

The wiring was essentially color-to-color between this Pioneer head unit’s harness and the Scosche wiring harness. Regardless, just compare the wire colors between your unit’s harness and the VW03B colors to be sure. The gray. white, purple, and green sets are your speakers. Yellow is “constant 12v” which is used for memory and such, while red is your switched power. Red is what is powering your head unit when your key is in the on/run positions.

Note: There is a Metra harness for the X3, the 70-9003, and I advise against it. It has a separate power wire for some reason (not pinned out), and additionally is lacking the CANBUS wires that you’ll need to retain steering wheel controls. The Scosche adapter has all pins populated and works well. You won’t use all pins, I simply popped out the extra leads from the VW03B adapter to make less wire spaghetti.

Other than the color-for-color connections, you’ll want to solder in additional wires from the ASWC1. The harness for this unit is intimidating, but we are actually only using 4 wires from it. Black, red, pink, and the black 3.5mm cable. You can unpin or simply tape up the remaining wires.

The black wire is soldered or tapped in with the stereo ground, the red wire is soldered or tapped in with the red stereo wire, and the pink wire is soldered or tapped into the brown wire corresponding with pin #9 on the vehicle. This was labeled “mute” or similar.

The programming process for the ASWC-1 is pretty simple, here is an illustration of pin #9 as well as the complete programming steps from Metra:

in summary

I was able to fish the microphone wire through the leather trim above the adjustable steering wheel, and then clip the microphone to the instrument cluster bezel. This made for good voice fidelity in calls, as well as looking relatively polished. The factory sound system, as I’ve discovered in the past, sounds much better with the new head unit. The total cost for this project was around $125, including the head unit, which I highly recommend (if you don’t need a physical CD slot) and have installed now in three of my vehicles.