Intermittent Electrical Issues on 2012

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Stonegrinder, Sep 29, 2018.

  1. Stonegrinder

    Stonegrinder New Member

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    2012 Prius
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    IV
    Wife's Prius is having intermittent, random electrical issues.

    First problem was AC/Heater Blower Motor quit working while she was out shopping. It was dark by the time she got home so I couldn't really do anything other than verify that it wasn't working. Next morning, I went out to check fuses, connectors, etc. and magically it was running fine. Turned car off/on and cycled the AC/Heat several times and it seemed fine. Off she went to work.

    Second problem. She gets in the car to come home that night and the dashboard lights are not their usual color. She says that they were "more blue than normal" and slowly drifted back to the regular color as she drove.

    Third problem. This morning she starts up the car to run some errands and the windshield wipers don't work. The rear wiper was fine. She turns the car off/on a few times and tries the wipers each time with no luck. She cleans the windshield off, runs her errands, and tells me about it when she gets home. I go out to investigate and the wipers are working fine.

    I have checked the fuse box and there is no moisture or other noticeable debris that would cause an electrical fault (at least none that I can see). The car has about 130K miles on it and has only given us 1 minor problem up to this point (bad door lock assembly).

    Any ideas? Thanks in advance for any help.
     
  2. fuzzy1

    fuzzy1 Senior Member

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    First thought & item to be checked :

    Weird stuff happening? MPGs dropping? Test The Battery | PriusChat

    If this car still has its original 12V battery, this is the time of year when impending failures are most likely to show up. But beware that the do-it-yourself test procedure in that post won't work for your Gen3 model.

    No guarantee that this is your actual problem, only that this is the first item (common and easily remedied) on the troubleshooting list.
     
    #2 fuzzy1, Sep 29, 2018
    Last edited: Sep 29, 2018
  3. Stonegrinder

    Stonegrinder New Member

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    Thanks for the info, fuzzy1.

    Any recommended method of DIY battery testing or do I need to bring the car to the dealer?

    I've got a digital multimeter and I know which end of the probes go where :)
     
  4. fuzzy1

    fuzzy1 Senior Member

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    If you have and can use a digital voltmeter, then you are most of the way there. Check the 12V battery (either at the battery under the trunk floor, or at jump point under hood) when the car as been sitting unused for a few hours, or better yet first thing in the morning, before going to READY mode. If the voltage is good, then go into an accessory mode, turn on headlights, and check again. This will tell you a lot.

    Be aware that just after the car has been running then shut off, the voltage will be artificially high for a while. And when the car is in READY mode, you will be measuring the charging system output voltage, not the battery itself.
     
  5. Stonegrinder

    Stonegrinder New Member

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    Thanks again, fuzzy1.

    Battery reads 12.6V after being left overnight. Headlights on drops it to 12.25V. Starting the car brings it up to 14.7V.

    Good, Bad, or Marginal?
     
  6. fuzzy1

    fuzzy1 Senior Member

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    That is good, so you can dismiss that battery as an issue.
     
  7. Stonegrinder

    Stonegrinder New Member

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    Cool, thank you. Guess we wait and see what else happens and haul it to the dealership.
     
  8. fuzzy1

    fuzzy1 Senior Member

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    I'm hoping of other owners to chime in here too, before you need to haul it in.
     
  9. Raytheeagle

    Raytheeagle Senior Member

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    Intermittent electrical issues:

    • How do the wires look?
    • any rodentia around or evidence they have been?
    • Any history of accidents or damage to your Prius?
    • How many miles and are you the original owner?
    Good luck and keep us posted (y).
     
  10. Stonegrinder

    Stonegrinder New Member

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    1) Wires look good. No obvious damage and a normal level of dirt & grime for a vehicle with >120K miles. I did check the fuse box for water/damage/debris and it looks fine.

    2) We have a fairly high number of suburban squirrels, rabbits, and critters but there is no apparent nibbling on the wires.

    3) No accidents or damage other than parking lot scrapes and dings. Only repair we have ever had done was having a bad driver-side door lock actuator replaced. That was done under warranty at the dealership.

    4) The car is my wife's, she is the original owner, and it has about 125K miles on it.

    Thanks in advance for any advice!
     
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