When wire car steering wheel controls, look at two areas: the device or system to control and the wires linking the wheel.
The steering wheel wiring is relatively straightforward because the wheels and linked devices are stock or factory units.
But when connecting aftermarket devices, such as the radio, the two might be incompatible.
So, here’s how to wire car steering wheel controls to an aftermarket head unit to take care of the incompatibility.
Table of Contents
- A Brief Look at Car Steering Wheel Controls
- How To Wire Car Steering Wheel Controls
- Functions of a Steering Wheel Audio Control Adapter
- Steering Wheel Audio-Control Adapter Head Unit Compatibility
- Installation Steps
- Step 1: Plan the Wiring
- Step 2: Disconnect the Battery
- Step 3: Remove the Stereo from the Dash
- Step 4: Link the Audio Control Adapter
- Step 5: Fit the Head Unit Back Into the Vehicle
- Step 6: Program the Steering Wheel Audio-Control Adapter
- Step 7: Test the Steering Wheel Controls
- Step 8: Reassemble the Dash Covers
- Wrap Up
A Brief Look at Car Steering Wheel Controls
Initially, vehicles only had a horn as the electronic component mounted on the steering wheel.
This connection relied on either wires that twist/untwist or brush/commutator arrangements.
However, the invention of the airbag required more reliable wiring for the driver-side airbag, leading to the development of the clock spring.
After the addition of this reliable electrical connection, it became possible to install more electrical functions on the wheel.
A clock spring on the steering column
Modern cars usually have various electricals on this moving part, including the following.
- Radio controls
- Paddle shifters
- Cruise control
Each vehicle has customized signals that the end devices can understand when you press these steering wheel buttons.
So, when you replace the factory radio with an aftermarket stereo, the signals might not make sense to the new system, meaning it won’t respond to your commands.
And some stock radios can be pretty basic. So, upgrading might be necessary to enjoy the benefits of having more features.
A factory car radio
How To Wire Car Steering Wheel Controls
You’ll need the following items for this installation.
- Steering wheel audio-control adapter (with its wiring manual)
- Aftermarket car radio (with its installation manual)
- Car stereo wiring diagram
- Wire stripper
- Electrical tape or wiring connectors (Posi-Tap)
Functions of a Steering Wheel Audio Control Adapter
Wiring these steering controls is relatively easy using a steering wheel audio-control adapter because it performs these five primary functions.
A person pulling a car radio from the dashboard
This adapter converts the digital or analog signals from the control buttons to a format the aftermarket head unit can understand.
Communication Protocol Conversion
The adapter also ensures the commands from the steering wheel are accurately transmitted and received by the car radio.
Steering wheel audio adapters can work with a specific set of car makes and models. Therefore, it ensures complete compatibility with your car because it is not a universal unit.
A person pressing the steering wheel control buttons
Most steering wheel audio adapters have a plug-and-play installation mechanism, making them easy to use.
Although most devices are plug-and-play, some allow programming to customize the functions of the steering wheel buttons to match those of the aftermarket stereo.
Steering Wheel Audio-Control Adapter Head Unit Compatibility
These adapters must be compatible with your vehicle and the aftermarket head unit, as well.
To confirm this compatibility, look for listed features like SWI (Steering Wheel Input) or wire remote control input.
Under SWI, some adapters specify the compatibility feature list details further into either of the following.
- SWI-JS: Refers to steering wheel input for Jensen and Sony aftermarket head units
- SWI-JACK: Steering wheel input for JVC, Alpine, Clarion, and Kenwood. This adapter is also compatible with some smaller head unit manufacturers.
- SWI-X: A universal standard that covers other brands and most generic aftermarket head units, especially those running on Android operating systems.
A factory radio
Follow these steps to wire your vehicle’s steering wheel control buttons.
Step 1: Plan the Wiring
Download the adapter’s installation instructions to plan the wiring cable by cable. And ensure the device is compatible with your vehicle and aftermarket radio before buying it.
Step 2: Disconnect the Battery
Before removing the stereo, disconnect the car battery’s negative terminal to avoid electrical incidents like shorting.
You’ll need a wrench or spanner to loosen the terminal and remove it from the lug.
Step 3: Remove the Stereo from the Dash
Pop the plastic dash panels around the head unit to access the screws that secure the stereo to the vehicle.
Next, loosen the screws using the screwdriver, then pull the radio out to access the wiring harness inside.
An electrician dismantling a vehicle’s head unit
If you’re replacing the head unit at this time, remove the connectors linking it to the electrical system and bring the new system on-site.
But if you had installed the aftermarket stereo earlier, unplug the wires and place it aside.
Step 4: Link the Audio Control Adapter
To secure the wiring connections firmly, remove the head unit harness from the dashboard.
Take the harness to a work table, then check the vehicle’s audio wiring diagram to determine the wires to hook.
Begin with the power and ground connections, usually red and black wires. You can peel these two wires from the radio harness to tap into them.
Solder the adapter’s power and ground wires into the two, then wrap them with electrical tape for insulation or use Posi-Tap connectors.
Next, connect the steering control jack interface to the back of the stereo.
This connection depends on the radio because it must be compatible (SWI or wired remote).
In some incompatible stereos, you might have to attach an adapter for the interface.
Step 5: Fit the Head Unit Back Into the Vehicle
Install the stereo back into the car and push the adapter down a little so you can see it. Screw the head unit into its slot, then proceed to step six.
An aftermarket car stereo unit
Step 6: Program the Steering Wheel Audio-Control Adapter
The audio control adapter must know which car it is in and the stereo you’ve hooked it to. So, program it while checking the onboard LED indicator.
First, reconnect the negative battery terminal, then turn on the ignition. The adapter’s LED indicator will start flashing.
Press and hold the volume button on the steering wheel, then wait for the adapter to complete its configuration.
You’ll know the process is complete when the LED stops blinking and stays on.
The programming process might differ depending on the adapter, so check its installation and configuration instructions.
Step 7: Test the Steering Wheel Controls
Once the programming is complete and the LED remains on, test the other radio control buttons. Ensure everything works before moving to the next step.
Step 8: Reassemble the Dash Covers
Wrap the loose wire using electrical tape, then secure the harnesses/looms in the dash using clips.
Next, reassemble the dash covers and test the steering buttons before certifying the installation as successful. That’s it!
A dismantled car dashboard
As you can see, wiring car steering wheel controls to an aftermarket radio is not a direct process due to compatibility issues.
But an audio control adapter creates a steering wheel control interface for compatibility to make the buttons functional in your vehicle.
Installing this unit is relatively straightforward if you understand the instructions in the manual.
This installation does not interfere with the steering side, but you can learn about the clock spring in this article to learn how to test and fix it.