... map/info toggle; steering wheel rocker switches ~

Discussion in 'Gen 2 Prius Audio and Electronics' started by asjoseph, May 9, 2015.

  1. asjoseph

    asjoseph Samuel, '04 Ruthiemobile

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    Dear Priuschat,

    ... in its 11th year of service, approximately its 145 thousand milestone, the right thumb MAP/INFO toggle switch was the first of the steering wheel rocker switches, to fail.

    Though an upward toggle of the "MAP" button still manipulates the MFD mapping function, it's only the downward selection, toggling to "INFO" which no longer does, necessitating default selection, manually reaching over to the left-of-screen INFO bezel, on the upper-left side of our MFDs.

    Question for you, if you please: has anyone thus far replaced these steering wheel rocker switches? How straightforward is an R&R, of any of these the various steering wheel switches? Doing so, do I risk air-bag detonation? Is there a link to an on-line graphic, an engineering diagram, or an instructional guide to our steering wheel available, which I might download?


    A Thousand Thanks,
    ~ Samuel, '04
     
    #1 asjoseph, May 9, 2015
    Last edited: May 9, 2015
  2. AzWxGuy

    AzWxGuy Weather Guy

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    The failure is probably in the clock spring multi-connector harness located inside the steering column. The usual mode of failure affects the switches on the right side of the steering wheel first. When mine began failing I lost the defrost, rear window defog, and air fresh/recirculate switches. A good test of this is to depress the info button and then turn the steering wheel through a couple of degrees either direction and see if at a certain steering wheel position it works again. I believe the clock spring replacement is rather expensive. I didn't get it done on my '08 before trading it in.
     
  3. ChapmanF

    ChapmanF Senior Member

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    I expect you can get to the switches themselves just by removing the air bag and covers, which shouldn't be hard, but you're right, you should make sure you understand how to safely disconnect, handle, and store the airbag. On the other hand, as the Weather Guy suggests, the problem might not be in the switches themselves but in the spiral cable (a/k/a "clockspring"). That's behind the steering wheel so you need to pop the wheel off to get to it. That's also not terribly difficult, and everything you need to know is also in the service manual. You can get that at techinfo.toyota.com which has all the kinds of information you were asking about in your first post.

    Having somebody replace the spiral cable for you might be an expensive proposition, but doing it yourself shouldn't be bad. The part itself from Toyota might be two or three hundred though. I think I've seen people post about buying aftermarket replacements for less. For looking up genuine Toyota parts and part numbers, Village Toyota has an excellent site.

    There's at least one post on here from someone who disassembled and repaired (with solder!) the spiral cable. I think I'd be leery of doing that (because, a, it moves all the time when you're turning the wheel, and rubs on itself, and b, hello, the airbag circuit runs through there!). On the other hand, if a spiral cable had only started making friction sounds while turning, but not showing electrical problems yet, I would consider opening it, inspecting to make sure there was no damage, and replacing the old sticky lube. Recently did that to mine, in fact. But if there were already electrical problems, as it sounds like you have, and they were in the spiral cable, I think I would go ahead and replace it.

    -Chap
     
  4. asjoseph

    asjoseph Samuel, '04 Ruthiemobile

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    ... that's an affirmative on your clock-spring check. Spinning that wheel around was pretty good exercise, for me (long story).

    Though, toggling down on the INFO button, spinning the wheel with my left hand, the MFD switched modes , from cartography back to the information screen. However, only did this occur, at random points along the steering wheel's circular range of motion. Though sometimes it engaged the information screen, first at 370 degrees counterclockwise, then again when turning back to 25 degrees clockwise, then at 85 degrees counterclockwise, it's never the same place, twice. No rhyme or reason, it's at no particular point on the wheel's rotation that a downward toggle of the INFO switch transmissions an impulse, to its MFD.

    This behavior far more indicative of cable fatigue, or friction induced wear, than a simple rocker switch failure, simply replacing the switch on the steering wheel won't work worth beans. This is unfortunate. I hoped this would be something simple. At this time, I won't be able to do this, myself. Post-op a big-big shoulder injury, it's going to be a little while before I'm working on cars, again -- Samuel, '04.
     
    #4 asjoseph, May 10, 2015
    Last edited: May 10, 2015
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