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2004 Prius - A/C info not working, some steering wheel buttons do not work

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by chrisgagne, Sep 6, 2008.

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  1. chrisgagne

    chrisgagne Junior Member

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    Hello,

    I have an early 2004 Prius, package #9, that I bought in 10/03.

    About 4-5 weeks ago, the "Info" button on my steering wheel began operating intermittently.

    A few weeks ago, the "Info" button stopped responding entirely and no longer responds.

    A couple of weeks ago, my A/C stopped working (no fan) but only briefly; it started working again after a drive or two.

    A few days ago, my A/C stopped again (no fan). When I drove over a speed bump, the fan kicked on immediately, and the air felt immediately cold (as though the compressor was running but not getting air passed).

    Last night, my A/C stopped functioning. The following steering wheel buttons do not function: Info, A/C Recirc., Front De-fog, Rear-defog. All other buttons work and beep immediately upon pressing.

    The Climate menu shows the outside temperature. When I turn the A/C system on or off, I hear relays clicking in the dash.

    All other components seem to be functioning nominal.

    I have checked all fuses listed as related to A/C in the user manual.

    I'm guessing that I either have a loose connection somewhere or a malfunctioning MFD. Any troubleshooting suggestions? Any assistance would be much appreciated. :)
  2. jdenenberg

    jdenenberg EE Professor

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    Your symptoms sound like the "MFD cracked solder" problem that is due to a manufacturing defect (misalignment of a connector tab an its solder pad). Toyota issued a TSB to do a warranty free replacement (first 36k miles) with a rebuilt MFD.

    You will either need to get a new MFD (expensive) or a salvaged one from a 2005 (not later as the design changed, not earlier or you will be subject to another failure) or look at a full description on how to repair one by "Hobbit".

    Prius MFD

    JeffD
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Chris,

    I had the MFD replaced under warranty on my 2004. When it failed, the MFD touchscreen was unresponsive while the steering wheel buttons continued to function.

    It appears that your symptoms are reversed, where the steering wheel buttons are not functioning while the MFD is working. If you agree, then I suggest the problem is with the steering wheel buttons or the wiring harness connectors leading to the button assembly.
  4. chrisgagne

    chrisgagne Junior Member

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    jdenenberg, thanks for the link!



    Hi Patrick,

    Thanks for your advice. Here's the symptoms from the TSB:

    • “Audio Off” is shown on audio screen while audio system is playing.
    • Climate control is not responsive and may say “Check connection of the
    • air conditioner.”
    • Map, Destination buttons are inoperative and may display “External system not connected.”
    • When pressing any button on the multi–display, the system takes 5 to 10 seconds to respond to the user’s input.
    • Outside air temperature is not displayed.

    My MFD doesn't have any of these symptoms, so it makes sense that something else is broken... It seems like the major issue with the MFD revolves around some sort of internal network connection failing. However, my MFD still gets outside temperature, etc. It's just the buttons and link to the A/C that's acting up, and even that link isn't 100% broken (I can still control recirculation shutter, etc).

    My A/C actually started up again today. Let's hope it sticks around for a while.

    Any recommendations for where I might start? Swapping out the MFD seems simple enough, but not certain to solve the problem. I can figure out how to check and reseat connectors to the MFD based on the MFD replacement guides that are out there, but I'm not sure where I would check the steering wheel wiring, etc.

    Is there a good wiring guide available online somewhere? Alternatively, is there a competent Prius mechanic in Los Angeles that won't charge me $4500 for a refurb MFD, only to not fix the issue?

    Finally, if I do need to replace the MFD, which MFD do I want if I have a package 9? 86110–47071 or 86110–47081? The 86110–47081 seems like it's going for $300-400 on eBay, which seems reasonable enough.

    Thanks so much for the help!!!
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Chris,

    I don't think that your MFD is the problem. To access the steering wheel switches it will be necessary to remove the driver's airbag, etc. You can obtain Toyota repair manual info at the following subscription website: techinfo.toyota.com

    If that is beyond your comfort level then it might be reasonable to let your local Toyota dealer handle the issue.
  6. chrisgagne

    chrisgagne Junior Member

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    Patrick,

    Thanks! I spoke with Steve over at autobeyours.com and he had the same advice - the MFD is probably OK. Before we diagnosed it as OK, he did offer to repair it for a very fair price - so a note to anyone else who is having trouble and DOES need a MFD fix.

    I'll check out the techinfo.toyoya.com website and get a sense of how difficult the repair is. Thanks again for all of your help!
    1 person likes this.
  7. chrisgagne

    chrisgagne Junior Member

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    Hi All, I figured I'd post an update to the thread. I never did get around to fixing the steering wheel buttons, but I DID fix the A/C:

    It turns out I had a busted blower motor... With AutoBeYours suggestion, I opened up the glove compartment and removed the cabin filter. I then checked the blower, and despite failing to find a dead squirrel or similar (Steve's suggestion), I gave the motor a bit of a turn and it SPRUNG TO LIFE, nearly removing a few of my fingers in the process. This pattern went on for a few more days before I overcame my laziness and installed a "new to me" blower motor purchased on eBay.

    Total cost: ~$45 for the motor, plus about $25 to Steve as appreciation for his time.
    1 person likes this.
  8. imwoody36

    imwoody36 the prius parts guy

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    Your Welcome!
    By the way folks,
    we offer mfd repair...please dont try it yourself.
    We have received many recently that have been ruined from improper repair attempts.
    Prius MFD Touchscreen Repair
    1 person likes this.
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