Steering Wheel controls

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ThatOnePrius, Nov 5, 2025 at 4:11 PM.

  1. ThatOnePrius

    ThatOnePrius Junior Member

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    2006 Prius
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    I'm trying to troubleshoot my steering wheel controls. I'm having issue with only 3 button not working. All others are working even cruise control.

    The Re circulation button, front and rear defrost button don't work. I can use the MFD touch screen to activate all three and they work no problem. I just cannot get them to work when pushing the button from the steering wheel.

    Things I have done-
    I've installed a new OEM clock spring. (The 3 buttons still don't work)
    I've installed another spare right side controls(The 3 button still don't work)

    The left controls work.
    The right controls, the Map/Info, Hands free, and both phone buttons work.

    I seen only a couple of threads with the same issue. The OPs replaced the clock springs but still had the same problem.

    I've looked at the wiring diagrams and it says when the Switch is pressed on the steering control it sends the signal to the A/C climate controller which then sends the signal to the relay. I'm assuming the relays are working because I can use the controls from the MFD to turn on the front and rear defrost and AC re circulation functions.
     

    Attached Files:

    #1 ThatOnePrius, Nov 5, 2025 at 4:11 PM
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    If you have a wiring diagram then you should measure voltages at the left and right side steering wheel switch assemblies.

    There's three wires. A signal circuit for the left, one for the right, and a common ("ground"). Each switch has resistors. Pushing any one switch connects that side's signal to ground though a "unique" combination of resistors. So front defrost has one voltage, rear defrost has another voltage, etc.

    All three wires come from the AC ecu, go through the clockspring to the left switch. The common and right signal are extended from the left switch to the right switch.

    You have to do voltage testing to find if the problem is the right side signal wiring (in the dash to the ecu), or the left switch (or connections), or the extension wiring to the right side (or connections).

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Nov 5, 2025 at 5:21 PM
  3. ChapmanF

    ChapmanF Senior Member

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    Yeah, this should be straightforward with a step-by-step troubleshooting method and the wiring diagram. You can pull up one of the MFD diagnostic screens that will show you what all the control button inputs are doing, and see if those show what you do with each button, and if some don't, you can check along the wiring path getting closer to the ECU and MFD.
     
    #3 ChapmanF, Nov 5, 2025 at 5:26 PM
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