BA32 Install Into CM5905 & CM5907


This article takes you through the installation process for our BA32 Factory+ Kit into the BMW CM5905 or CM5907 radio. The installation process is identical for both radios.

Kit Contents

Check your box to ensure you have all the contents. You should have:

  1. BA32 board w/ 2 screws pre-installed on either side
  2. Microphone w/ clip
  3. 5-pin wire harness
  4. Mic/aux cable


Step 1: Cassette Deck Removal

The first step is to remove the radio from the car and remove its factory cassette deck. For this series of steps, you can follow along with our install video for the previous generation product from the beginning until about 4:30 where the cassette mdechanism is removed from the radio.

Step 2: Mounting Tabs Transfer

Transfer the mounting tab attached to the cassette mechanism's back right corner to the BA32 board. Use the screw that came pre-installed in the BA32 board to install. Hold the mounting tab level as you tighten down the screw.

Step 3: Volume Harness Replacement

Remove the 5-pin harness attached the circuit board behind the volume knob. Grab the base of the wires and rock side to side while pulling towards the rear to remove. Replace with the white or black 5-pin wiring harness included in the kit. Push the harness firmly into place and give it a light tug to ensure it's securely held.

Step 4: Board Install

Get ready to insert the BA32 circuit board into the radio chassis. Remove the screw that came pre-installed in the terminal at the back left of the BA32 board and set it aside for a moment. Get all harnesses clear from the canter area where the board will sit.

Insert the board down into the chassis starting at the rear. Route the white flat cable from the cassette mechanism through the hole in the board. 

Ensure that the two mounting tabs are sitting on their screw holes and install the screws to secure in place. Reinstall the ground strap removed previously onto the back right mounting tab.

Align the back left corner of the board vertically so that you can see the screw hole through the chassis, then use the screw pre-installed in the BA32 board to attach the back left edge through the chassis.

Step 4: Board Connections

The next step is to go around and connect the various electrical connections to the BA32 board. Tackle this in the following sub-steps:

  • The 5-pin harness at the left rear connects to the receptacle labeled "Main Power"
  • The 4-pin harness at the front right connects to the receptacle labeled "Line Out"
  • The 5-pin harness removed from the volume knob circuit board connects to the receptacle labeled "Volume OUT"
  • The 5-pin harness that's now installed into the volume knob circuit board goes into the connector labeled "Volume IN"
  • The wide, float flex cable goes into the receptacle labeled "Main Cassette". The receptacle has a locking sleeve, so start by pulling the sleeve upwards to unlock it.

    Insert the cable into the slot of the connector and push downward as far it will go.

    Push the locking sleeve downward to lock. If properly inserted, there should be no exposed metal leads once locked

Step 5: Mic/Aux Cable Install

Connect the external mic/aux cable included in the kit to the receptacle at the back right of the BA32 board.

Next we'll route the cable out of the radio. If the cable doesn't already have one, we recommend tying a single knot in the cable to act as a strain relief. Route the cable as show through the small slit in the radio chassis.

Step 5: Reinstall In Vehicle

The remainder of the install is the reverse of removal. See the video below starting at 6:53 until the end: