[Motorsport-Werk]

Retrofitting Paddle Shifters to a Non-Prewired BMW G20

When I decided to retrofit paddle shifters to my BMW G20, I couldn’t find a complete guide tailored to non-prewired vehicles. After successfully completing the process, I wanted to share my experience so others can benefit from clear instructions and avoid guesswork. This guide includes detailed steps and clear explanations to make it easy for everyone, even novices, to follow.

As a side note, I was unable to find a ready-made cable online for this retrofit. To solve this, I worked on creating a suitable product, now available at my store, Motorsport Werk. I also offer optional remote coding services to simplify the final step, but please know this guide is meant to help anyone, regardless of where they choose to source parts or services.

Preparation
Before starting, gather the following tools and materials:

Parts & Services:

• Retrofit cable - DIY or buy a made one. If needed, you can find the one I created for sale here: Shop-Link.
• This includes the correct pins and length (I think 1.3m) for routing from the BDC to the SLZ.
• VO coding.

Tools:

• Trim removal tools.
• Screwdrivers (flathead and Phillips).
• 8mm socket and wrench (for SLZ access).
• Torque wrench.

Safety:
Disconnect the battery before beginning to avoid electrical damage or airbag deployment risks.

Step-by-Step Process

Step 1: Access the BDC Module
The Body Domain Controller (BDC) is located in the passenger footwell. Follow these steps to access it:

• Remove the door sill trim and the cover near the bottom-right corner of the door frame, next to the passenger door.
• Gently detach these trims using a trim removal tool. No screws or bolts are involved in this step.
• Locate the BDC connector and find Pin 5.
• The first and last pins on the connector are numbered for easy reference.
• Pin 5 is in the first row, counting from the left.
• Insert the cable pin securely into Pin 5 after you have routed the cable, and plugged the other end at the SLZ Pin 3 first. It should click into place without much pressure.

Step 2: Access the SLZ Module
To connect the other end of the cable to the SLZ:

Remove the Steering Wheel:

• Detach the airbag by releasing the clips using a flathead screwdriver. Disconnect the airbag connector and set it aside safely.
• Unscrew the central bolt (16mm) with a torque wrench and remove the steering wheel.

Access the SLZ Connector:

• Remove the leather trim between the dashboard and steering wheel using a trim tool.
• Remove the upper and lower plastic steering column covers. Be cautious of cables attached to the lower cover.
• Unscrew the 8mm bolts securing the SLZ module.
• Open the SLZ connector housing using the release mechanism.

Insert the Cable Pin into Pin 3:

• Refer to the attached image for clarity on locating Pin 3 in the SLZ connector.
• The pins are numbered, with Pin 1 at the top-left corner of the first row. Pin 3 is the third pin in the top row.
• Insert the cable pin into Pin 3. It should click securely into place.

Step 3: Route the Cable
To connect the BDC to the Steering Column Module (SLZ):

• Route the cable starting at the SLZ:
• Guide the cable down from the Steering Column Module (SLZ).
• Pass it through the trim below the steering wheel and into the center trim under the infotainment system.
• Continue routing it behind the dashboard trim on the passenger side.
• Bring it past the passenger airbag switch.
• Finally, route the cable down into the passenger footwell to the Body Domain Controller (BDC).
• Insert the cable pin into Pin 5 of the BDC connector.
• The BDC connector has numbered pins, with Pin 1 at the start of the row.
• Ensure the pin clicks securely into place.

Step 4: Reassembly

• Reconnect the SLZ module and secure all with its bolts.
• Reinstall all trims and covers, ensuring they are properly aligned and secured.
• Reattach the steering wheel:
• Align the notches on the steering wheel and column.
• Tighten the central bolt to the specified torque.
• Reconnect the airbag and ensure it is properly seated.

Step 5: Coding
For coding, you need to update the Vehicle Order (VO) to include 2TB (Sport Automatic Transmission), replacing the standard 205.

If you prefer to code the car yourself, tools like Esys can be used.

Why I Wrote This Guide
I wrote this guide because I couldn’t find clear instructions for retrofitting paddle shifters in a non-prewired BMW G20. I’ve also worked on making this process easier for others by offering a compatible retrofit cable and coding services. However, I want to emphasize that this guide is intended to help everyone, regardless of where they source their parts or services. My goal is simply to share what I’ve learned and make this upgrade more accessible.

Tips & Additional Notes
BDC and SLZ Pin Locations:
The BDC connection goes into Pin 5, while the SLZ connection goes into Pin 3. Both connectors are numbered at Pin 1 with a big "1" for easy identification. Refer to the attached image for the SLZ pin layout.

Cable Management:
Take your time routing the cable to ensure it’s neat and secure. Avoid sharp bends or interference with moving parts.

Testing:
After reassembly and coding, test the paddle shifters in manual mode to ensure they’re functioning correctly.

Important Note: Options for Retrofitting Paddle Shifters on a Non-Prewired G20

For anyone following this guide, I wanted to share some additional information to help you plan your retrofit. Depending on your current setup and preferences, there are two main options for adding paddle shifters to your G20:

Option 1: Retrofitting Paddle Shifters to Your Existing Steering Wheel
If you want to keep your current steering wheel:

• You’ll need to add the paddle shifters and retrofit the wiring.
• This requires:
  • Cutting or modifying the backplate of your steering wheel (if it doesn’t have paddle cutouts).
  • Installing the correct wiring harness for the paddle shifters.
  • Following the main guide to connect the wires to the SLZ and BDC.

Option 2: Replacing Your Steering Wheel with a Pre-Fitted Paddle Shifter Wheel
Alternatively, you can purchase a steering wheel that already includes paddle shifters:

• Ensure Compatibility:
  • For example, upgrading from a Sport Line steering wheel to an M Sport steering wheel will require a different airbag.
  • The Sport Line airbag is not compatible with the M Sport steering wheel, so you’ll need to source the correct airbag if making this change.
• Wiring Considerations:
  • If the new wheel comes with pre-installed paddle shifters, ensure it includes the wiring harness that connects the paddles to the SLZ.
  • Follow the main guide for connecting the wires to the BDC and coding the car.

Final Tips

• If you’re upgrading to a new steering wheel, double-check the airbag and connector compatibility before purchasing.
• Make sure the new wheel is designed for your G20 and has the correct cutouts for paddles if needed.
• Whether retrofitting paddles or installing a new wheel, remember to disconnect the battery before working on the airbag or steering components.

Feel free to ask any questions or share your experiences—happy retrofitting!