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Display died after 12v died

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PriusMatt, Nov 20, 2020.

  1. PriusMatt

    PriusMatt Junior Member

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    Hi there,

    Searching, I haven't found this exact situation.

    Due to Covid, we haven't been using our 2007 Touring too often. After months of not using it, I got in and the 12v was dead dead. Couldn't revive with a trickle charger so bought a new 12v and replaced it myself since it had been awhile. We've got somewhere around 96k miles on it.

    After installing the 12v, I drove it once or twice and when I put the car in reverse, it would take about 10 seconds or so before the backup camera would show up. Now, about 2 weeks later, I get in the car again and the screen is completely black.

    Is there something I did wrong in the install? All the connectors seemed to click firmly. From reading, seems like I should check the fuses but other than that, not sure what to do.

    Thanks,
    Matthew
     
    #1 PriusMatt, Nov 20, 2020
  2. PriusMatt

    PriusMatt Junior Member

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    hmm. this post didn't seem to show up in new posts, so commenting to maybe bump it up.
     
    #2 PriusMatt, Nov 20, 2020
  3. bisco

    bisco cookie crumbler

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    it's possible that installing the new battery blew the board on the monitor. it happens
     
    #3 bisco, Nov 20, 2020
  4. PriusMatt

    PriusMatt Junior Member

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    guessing that would mean full replacement of the monitor with a new or used one?
     
    #4 PriusMatt, Nov 20, 2020
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    Definitely not a new one....those are around 5k or so....

    You'll need to get the model number from the back of the MFD if you want to replace it. There were several models depending on year and options on the car. You really want to have matching numbers. If you opt for repair, I think there are several places that will refurb for a few hundred $$.

    Does the radio still work when the MFD is dead?
     
    #5 TMR-JWAP, Nov 20, 2020
  6. PriusMatt

    PriusMatt Junior Member

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    STRANGE! I just went to move the car into the driveway and check if the radio worked. Pulling up, the ICE kicked in, then 3 seconds later, the Toyota splash screen appeared and then the display was working. Engaged reverse and the camera worked! Is it possible that the regular 12v battery was just a little low from sitting for about 2 weeks, then the ICE charged both the 12v as well as the regular rechargeable batteries?

    ps - radio DID work when I first got in the car and there was a blank screen.
     
    #6 PriusMatt, Nov 20, 2020
    Last edited: Nov 20, 2020
  7. bisco

    bisco cookie crumbler

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    anything is possible, you should test it.

    you may also have a loose connection behind the h/u, or loose battery connections. also chaeck the 12v negative to ground point.
     
    #7 bisco, Nov 20, 2020
  8. PriusMatt

    PriusMatt Junior Member

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    sorry, I'm not sure what the h/u is.

    also, where is the 12v negative to ground point? I'm guessing off of the 12v battery that I installed? - I don't remember off hand all the various connections I put back in place.

    sorry for beginner questions.

    thanks for your help!
     
    #8 PriusMatt, Nov 20, 2020
  9. dolj

    dolj Senior Member

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    Yes, that is correct. The 12V battery has two terminal posts a positive and a negative. Orient the battery so both posts are nearest to you (and assuming you have the correct battery), the positive (red) post is on the left and the negative (black) is on the right. The negative post will have a short strap connecting it to the car body. Both connections needed to be clean and tight. The end connected to the battery also needs to be pushed right down to the bottom of the post and tightened without out it moving up.

    The positive on the Prius has a black plastic terminal block and its connection to the battery also needs to be clean and pushed right down to the bottom of the post. It also needs to be tight. If you can't get either terminal clamp to go to the bottom of the terminal post, loosen the bolt right off and use a large flathead screwdriver to lever it wider apart so you can just drop it right down with no friction.

    Intermittent power problems often are caused by one or more of these connections being loose.
     
    #9 dolj, Nov 20, 2020
  10. PriusHead05

    PriusHead05 Member

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    h/u could be "hook up" could be "hybrid unit". Not exactly sure what it is. Never seen that term before. The negative to ground is directly at the battery. It screws into the body.
    Posted via the PriusChat mobile app.
     
    #10 PriusHead05, Nov 22, 2020
  11. PriusHead05

    PriusHead05 Member

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    Also, you will see the term MFD, which is the screen that you are referring to. It stands for Multi-Function Display. Beginner questions are good.
    Posted via the PriusChat mobile app.
     
    #11 PriusHead05, Nov 22, 2020
  12. dolj

    dolj Senior Member

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    H/U usually is the shorthand for the head unit (and usually is referring specifically to the radio head unit).

    Check also that all the connections in the back of the multi-functional display (MFD) are clicked in securely.
     
    #12 dolj, Nov 22, 2020
  13. PriusMatt

    PriusMatt Junior Member

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    Thanks for the responses! The craziness of the holidays took me away from trying to fix this problem. I disconnected and reconnected the battery connections. They were all clean. I lowered one of the terminal connections as far as I could by lightly hammering it down with a piece of wood. The connections all seem to be pretty solid.

    The problem is now sporadic. On occasion, it works fine. Then, maybe a few minutes later, the screen will just go blank. One time the screen turned to about 20 or so vertical stripes, and then later - a hazy full screen where I could just vaguely see the Toyota logo. The sporadic nature of this leads me to thinking that it is perhaps a bad relay.

    Does anyone know which relays and/or fuses I should replace as an attempt to fix this (if that is indeed what the problem is)?
     
    #13 PriusMatt, Jan 1, 2021
  14. edthefox5

    edthefox5 Senior Member

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    You have a bad mfd look on ebay there is hundreds of them all $125-200.

    Anyway pay more attention to the hybrid battery that's next on the I don't drive anymore and it died. That will be substantially harder and way more expensive to fix that the 12v and the the mfd and the car is a brick with a dead hybrid battery.
    More you let the car sit the sooner that's coming.

    Also amazed your catalytic converter has not been stolen. Just about every CA poster on here has lost theirs and it is expensive like $2200 all in to replace the cat & 02 sensor and repair the wiring they destroy stealing your cat. In CA you must use the factory original Cat they check thats the real deal under the car.

    Its epidemic in CA. I just sold my Cat on eBay got $1350 for it bidders like crazy.
    People are desperate to save any kind of money on that they can.

    Go on youtube and search:

    Prius Stolen

    lots of good CA cat info. or use the search forum link up top and search Cat or just use Google and search it. Its nation wide now on all kinds of cars precious metals have gotten very very expensive.
     
    #14 edthefox5, Jan 1, 2021
    Last edited: Jan 1, 2021
  15. PriusMatt

    PriusMatt Junior Member

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    oh I've had the cat stolen. neighbors camera showed that it was exactly 2 minutes from them driving up, getting it, and driving away. sucked. made an insurance claim on that.

    you don't think the relays might be the case? guessing you've seen enough of these postings to feel confident it's the mfd itself.
     
    #15 PriusMatt, Jan 1, 2021
  16. dolj

    dolj Senior Member

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    Yes, usually. autobeyours.com repairs them (Prius Flat rate MFD Repair with 12 month warranty), I believe, and that involves reflowing the solder on pins on the edge connectors. But don't quote me on that is all they do.
     
    #16 dolj, Jan 1, 2021
  17. edthefox5

    edthefox5 Senior Member

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    no ......relays don’t put lines in the picture it’s done, yeah I was surprised about your cat its like now if you stop at a light out there you got a guy going at it under the car with a sawszall lol...
    Did you see the video the 5 guys rolled a Prius over on its side and cut the cat off in London.
    It all started in London first.

    careful they may deny a second cat theft........

    not a good car to own in Ca. There driving around looking for you but now they know where you live many posters on this site hit multiple times
    They know in Ca you have to have that sweet OEM cat .......
     
    #17 edthefox5, Jan 2, 2021
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