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Replacing a power mirror switch--am I missing something obvious

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Scott_R, May 15, 2023.

  1. Scott_R

    Scott_R Member

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    The power mirror control switch has been acting up the last couple of years (2012 Prius, model IV).
    OEM replacement from Toyota was about $200, so I went on eBay an found one that eBay's vehicle selector said would fit, and the seller had 2012 Prius listed as compatible.

    But the wiring harness wouldn't fit--the new and old sockets looks pretty different.

    Original is on the right; there's no way the other should fit, is there? The pins are a different shape and there are different numbers. But when I look at other sellers on eBay and sellers on Amazon, they all look like the new, incompatible one I received.
     

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    #1 Scott_R, May 15, 2023
    Last edited: May 15, 2023
  2. bisco

    bisco cookie crumbler

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    i would contact the seller. either they are incorrect, or they shipped the wrong one
     
  3. Scott_R

    Scott_R Member

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    But I don't see any sellers on Amazon or eBay that have this part for a 2012 Prius 4 that has the same socket as the one I have--they all look like the seller's. Maybe they're using a generic picture instead of the actual one, but everyone I've seen looks like the one from the seller I bought from.

    I've sent a message to the seller, but I've been unable to find a part that looks like mine when searching for a 2012 in trim 4.
     
  4. bisco

    bisco cookie crumbler

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    i would contact some dealers to see if anyone stocks it
     
  5. ChapmanF

    ChapmanF Senior Member

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    This is what's shown in the wiring diagram for a Gen 3 (happens to be 2010 edition I'm looking in).

    Does look more like the seller's, now, doesn't it?

    L18.png

    Hmm ... I hesitate to recommend parts.toyota.com since they've so badly fubared it recently, but 2012 was a Gen 3 mid-cycle refresh, and maybe it's worth looking ... somewhere official ... to find out if there was any change in part number for this thing.

    Does yours look, on the visible side, like it would have any kind of different functionality than the one the seller sent?

    According to ToyoDIY, for 2012 model year, there was a change after November 2011 build date:

    Code:
    84870A SWITCH ASSY, OUTER MIRROR
    84870-28030 (12/2011 - )
    84870-34010 (04/2009 - 11/2011)
    
     
    #5 ChapmanF, May 15, 2023
    Last edited: May 15, 2023
  6. Scott_R

    Scott_R Member

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    Thanks for the reply.

    The original and eBay part I received look identical on the face (see below).

    I'd done some further searching on OEM (I presume) parts sites and with my VIN came across that 84870-28030 part, though for some reason it's always a sketch, not a photo, and never shows the back side, so I can't confirm the pin layout. I have yet to find a non-OEM replacement part that matches. Do I want to spend $130+ for something that I only occasionally use? I'm not sure, especially without confirming the plug really matches, and from what I can tell in the sketch the 84870-28030 has that added folding mirror button, and I definitely don't have that feature though it would explain the additional pins.

    When searching at Toyota, why does the 28030 bring up something that looks nothing like it?
     

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    #6 Scott_R, May 15, 2023
    Last edited: May 15, 2023
  7. ChapmanF

    ChapmanF Senior Member

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    You mean, why do you get a picture of an engine with knock sensors and O₂ sensors, instead of a picture of the part you're looking for?

    Well, y'see, it's like this. Up until a couple weeks ago, Toyota had a parts web site that worked. Did I mention they fubared it since then?

    Doesn't make me happy either.

    I'm not sure about the folding button in the pictures. Here's a dealer listing where the sketch of the part does not show a folding button:

    https://parts.longotoyota.com/oem-parts/toyota-mirror-switch-8487028030

    (Hey! It's also a dealer that still has their own working parts web site! Lots of dealers used to, but I was starting to worry that they had all been told to use the new broken one from the mothership.)

    My mirror switch (2010, the earlier style) didn't work when I bought the car. Dead as a doornail.

    I opened it and carefully cleaned the contacts with GC Jiffy Bath (which I've had a can of since forever) and it's been fine ever since.

    Toyota expressly says never to do that ("DO NOT attempt to repair a malfunctioning switch. Replace it. The use of any cleaning fluids may cause additional damage."), so I don't intend to blame them if my Jiffy Bath'd mirror switch conks out, and you didn't get the idea from me, whether you use the same stuff I used or try something else.
     
  8. Scott_R

    Scott_R Member

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    It's frustrating that this one part is always shown as a sketch without a view of the socket and pin layout.
    I'd considered using contact cleaner, but with the replacements being $130-$140+ I'm thinking twice, especially as the current one sort-of works.
     
  9. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Rock auto has the Dorman-branded part for about $54 and they're 1000% better than eBay in terms of making sure it fits.

    ...i'm not saying I know for sure theirs is correct, just that I have seen them work hard to make certain their catalog is accurate and bend over backwards to support customers when there is a fitment mistake.

    Edit: adding:

    I looked directly into Dorman's catalog and found some interesting bits: they've got a nice interchange map including cross-applications.

    However, their picture of the connector looks like this:

    Screenshot 2023-05-16 at 8.21.08 AM.png
    which isn't encouraging..
     
    #9 Leadfoot J. McCoalroller, May 16, 2023
    Last edited: May 16, 2023
  10. Scott_R

    Scott_R Member

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    Do you have a link for the part? I'm having no luck finding it there. The only Dorman switch I'd seen elsewhere (Amazon) had the same socket layout as the one I'd gotten from eBay.
     
  11. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Here's a link to what both Rock Auto and Dorman think is the correct Dorman part: 901-729 Mirror Switch

    From the photo, I see the same mismatch.

    Crazy theory:

    Not the first time the switch was replaced, and the previous repairer knowingly used a switch that fit the hole and then spliced on the matching pigtail from the donor car?
     
  12. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I'm scratching out my crazy theory, though it may be a useful cure for this situation.

    I did more poking around. I looked at the cross-applications for the Dorman 901729, trying to work out which Toyota cars were not on it, because they might be a good bet to be the root application of the switch that was re-purposed for early-2012 Prius vs.

    Best hit was the 2011 Corolla. Again, the 901729 does NOT fit this car. Then I did a fresh lookup of the mirror switch for the 2011 Corolla, and I hit the same OE part number @ChapmanF found in his post above: 84870-34010.

    And to close the loop I searched both Rock Auto and Dorman for a mirror switch for the 2011 Corolla: they haven't got one.

    I think if you search for the 84870-34010 or by application "2011 Corolla" you'll find the part you need. But I'm not optimistic that you'll find it any cheaper than Toyota.
     
  13. Scott_R

    Scott_R Member

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    I'm the original owner, so if it was replaced it was somehow, for some reason, done without my knowledge.
     
  14. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Better parts mystery than usual, unfortunately.

    If I get more time later I'll take another crack at it.
     
  15. Scott_R

    Scott_R Member

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    I think it's the 84870-28030; AFAIK the 34010 is the one with the 7-pin socket. But I can't find an image of the back of the 84870-28030 to verify.
     
  16. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Yes, I think you are right. I think I pasted in the wrong number to properly compound the error.
     
  17. ChapmanF

    ChapmanF Senior Member

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    My guess is that anybody whose TIS access is currently paid up could glance in the Electrical Wiring Diagram for a 2013–15 and see the picture of the connector, and it will look like the new one.

    Toyota Service Information and Where To Find It | PriusChat

    I wonder what will be shown in the 2012 EWD, as the change appears to have happened in the midst of that model year. I am guessing it will show both versions, with asterisk notes.

    @Elektroingenieur?