Auto-Dimming mirror on pre facelift Prius v?

Discussion in 'Prius v Accessories and Modifications' started by gromittoo, Nov 17, 2021.

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  1. gromittoo

    gromittoo Active Member

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    I have Two Prius v's, a 2013 two which I drive heavily for Uber, and a 2017 four that my wife mostly drives to work. Shortly after getting the 2017 four, I complained that the auto-dimming + Homelink Mirror was too heavy. I complained it was a pain to re-adjust the mirror when switching drivers.

    I have changed my mind. I am tired of getting blinded. Driver switches don't happen as often now that my daughter is back in school. Also, instead of 14 hours of daylight in the summer, I am experiencing 14 hours of darkness in the winter. And there are those idiots who install those blindingly bright light bars on their cars that I think should be illegal for on-road use.

    I recall that @rjparker replied that he installed an auto-dimming + Homelink Mirror on his 2012 Prius v. Anybody care to comment about putting either a Toyota or aftermarket Auto-dimming mirror? How difficult was the retrofit? I know there is switched 5 volt power in the dome light console for the hands free microphone. I would like to wire my dashcam into that at the same time.
     
  2. rjparker

    rjparker Senior Member

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    Yes I did it early on for my v3. However I found no switched 12v in the area. Apparently the harness includes sw12v only on the v5 with Homelink from the factory.

    The mechanical fitting was easy and I bought the wiring cover for the mirror to the headliner wiring. I powered the Homelink mirror from the constant 12v after I found standby current is only 6ma. Even when you have switched 12v, the Homelink buttons stay powered when the car is off. It is the autodimming function that normally runs off the switched 12v.

    As you have seen on your 2017, the auto dimming is seamless and reasonably effective. My primary goal was the three button homelink gate/garage door functions.

    Gentex makes the Toyota mirror and the "aftermarket" units.
     

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    #2 rjparker, Nov 17, 2021
    Last edited: Nov 18, 2021
  3. jzchen

    jzchen Senior Member

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    I couldn't remember where I saw them before/what brand, so I Googled it. I found these interesting, but no experience retrofitting I'm afraid. I did find the old flip switch worked well for me, at least when flipped "up" at night, meaning the reflection of light shined up at the ceiling, vs downwards towards my lower face. This sometimes required minor adjustment to center the rear window...

    https://www.voxxelectronics.com/gentex/
     
  4. gromittoo

    gromittoo Active Member

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    Thanks. I live in a 100 year old cape cod on a 50 foot wide lot. I am lucky to have a driveway where I live. I don't think I will ever use the Homelink.

    If I do install an Auto-dimming Mirror, I would want to get rid of the Dashcam wire at the same time. I want to kill two stones with one bird, so to speak.

    I recall seeing a post in some Toyota related forum where someone was trying to power a dashcam with switched power from the dome-light. I recall that the Dome light assembly contains a Switched 5 Volt for the microphone, and an un-switched 12 volt. Dashcams draw a lot of current, so he used the switched 5 volts to power a relay to provide switched 12 volts, and then used a module he bought on alibaba to bring that 12 volts down to a 5 volts, that can support the high current needs of a dashcam. I would use a 12 volt cigarette lighter to USB plug from the dollar store.

    I should have bookmarked the post.
     
  5. gromittoo

    gromittoo Active Member

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    The flip style has always worked for me, and the "flip" happens to be the exact change in angle between my wife (who is shorter) and myself. I like that it only takes two fingers to perform the flip. At worst, I can adjust the old style mirror with one hand still on the steering wheel. The Auto dimming mirror requires both hands to adjust.

    My problem is that people have been retrofitting their cars to have these extremely bright forward facing lights. Even Factory LED headlights are problematic. My Cataract surgery has helped a lot, but the constant change in the size of my pupils means I start seeing halos after 5 hours of night driving.

    I Uber in Philadelphia at night a lot, and I find switching back and forth from day to night getting really tedious, and potentially dangerous if I leave the mirror in "Night" mode when I need "Day" mode. Most of the time, I want to drive in "Day" mode, except when followed by someone with extremely bright lights.

    BTW: Thanks to @rjparker for the diagrams. Any chance of getting the diagram of the microphone board, so I can find the switched +5volts?
     
  6. rjparker

    rjparker Senior Member

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    The drawing does not specifically call out +5v but you could easily test with a meter. However I think the cleaner solution would skip the 5v relay run by the mic's 5v. First there is very little extra room up there for anything.

    I would just run a cable up from the usb power supply located down by the powerport. While you are at it, bring the powerport's switched 12v with it. I would use an 18 gauge four conductor cable. Probably could hide most of it behind the dash or the powerport assembly.
     
    #6 rjparker, Nov 18, 2021
    Last edited: Nov 19, 2021
  7. gromittoo

    gromittoo Active Member

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    Dashcams and radar detectors still use the old "Mini" USB, and not the "Micro" USB for a good reason. Both devices draw a lot of current. That is to say my several year old dashcam consumes more current than can be reliably sourced through a "Micro" connector, so it uses the now obsolete Mini USB. If USB-C had been more popular when VanTrue began making dashcams, they might have used USB-C.

    The posting I read (and can't find) expressed concern about burning out the 5V section of the microphone board if used directly. I recall the post had pictures, and they had tack soldered a transistor or something to the 5 volt microphone supply, to connect the 12 volts from the lighting circuit to a 12v to 5v converter module they had purchased on AliBaba. I prefer using a relay, because it offers isolation between the two voltage lines. If I take a really small Cigar lighter to USB supply, and take remove the outer part, I will have the requisite 12 volt to 5 volt converter, and a USB type A female plug. A little solder, and some hot melt glue to pot the whole mess....

    I have to figure out how to get the dome light assembly down first. I was not successful yesterday.
     
  8. gromittoo

    gromittoo Active Member

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    Another option is the following on Amazon:
    (search amazon for Item ID B07G9WTWB9 if the link does not show up below)


    This is the kit for wiring in the dashcam to the fusebox, via wires you have to hide yourself.
     
  9. rjparker

    rjparker Senior Member

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    That 12v to 5v self contained power supply is what I was talking about when suggesting you skip the 5v relay.

    To drive a five volt relay from a line that was not designed for it normally requires a transistor circuit as you describe. In most cases the dc relay would have a reverse biased diode across its coil and often a resistor to limit current. While not rocket science, a bad part selection or misplaced connection could smoke the source, in this case, your head unit.

    While its been many a moon since I removed the map light assembly, the bottom has two push in clips and the top has (at least) two slide in retainers. See pics. Release the bottom first.

    DD9C7235-191D-46A1-B05E-C452FB17B872.jpeg

    304D8BD0-374F-499F-9EA9-2B283D1022D4.jpeg
     
    #9 rjparker, Nov 19, 2021
    Last edited: Nov 19, 2021
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  10. gromittoo

    gromittoo Active Member

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    Wow! thanks @rjparker! There is nothing better than pictures to see what you are attempting to pry off.

    I am thinking that if I can't fit the 12 volt to 5 volt converter inside, I will run 3 wires down to the back side of the rearview mirror:
    - Ground
    - Switched low current +5 volt
    - Unswitched +12 volt.​

    I would make a small box to hide the converter (mounted to the back of the rearview mirror), and have a 12 inch lead with the high current +5 volt run to the dashcam.

    I need to find that post. That person worked out the details of using the switched 5 volts to create switched 12 volts, and I believe they were able fit it in their version inside the dome assembly. The relay I was considering was cube about of about 1cm, and can handle 1 amp. It does not draw much current.
     
  11. gromittoo

    gromittoo Active Member

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    A little poking around before I go out driving. The moonroof switch compartment is handy, as I can put a rocker switch for dashcam. This would allow me to turn off the dashcam if a passenger requests it.

    upload_2021-11-19_13-32-57.jpeg
     
  12. GeorgeS

    GeorgeS Junior Member

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    We have a 2013 Prius V and do not like the auto dim mirror. It does not dim soon enough for me. Also it seems to revert to day too soon. How can the sensitivity be controlled? If I turn the auto feature off, how do I force it to the night setting?
     
  13. rjparker

    rjparker Senior Member

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    It takes about 5 seconds to dim. Turning it off with the right buttons leaves it in day mode. The v2 and v3 models had conventional flip mirrors which you could buy used for low dollars. Almost any genteq mirror could also be used and might have better features.
     
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