1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2018 PP+ dome light switch

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by pbasch, Sep 12, 2021.

  1. pbasch

    pbasch Junior Member

    Joined:
    Jan 3, 2011
    38
    10
    0
    Location:
    Los Angeles
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Lately, the dome light doesn't come on when I open the door. The switch is in the middle, flat position. When I touch the switch to check that it's not "off", the light goes on intermittently. I believe that's a sign that the switch has an intermittent. I'm going to the dealer for regular service at some point, so I was going to mention it, but if it's easy to remove the cover and spray some contact cleaner in there, I would do that. Maybe it would work... Is that an easy cover to remove? Or am I on the wrong track altogether?

    EDIT -- should have mentioned, when I touch the switch (with the door open), the light goes on momentarily, but also, so does the rear light. That's why I suspect it's the switch rather than the bulb.
     
    #1 pbasch, Sep 12, 2021
    Last edited: Sep 12, 2021
    Zzz likes this.
  2. rdgrimes

    rdgrimes Senior Member

    Joined:
    Jun 7, 2013
    1,740
    444
    4
    Location:
    New Mexico, USA
    Vehicle:
    2018 Prius Prime
    Model:
    N/A
    I'd start by replacing the bulb.
     
  3. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    10,958
    8,836
    0
    Location:
    New England
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Yeah, if the car is still under warranty, and you don't mind stopping by a dealer, then let them take care of them. If it is out of warranty, then that would be a different story. Then I would try to fix it DIY before taking it anywhere. If DIY, first check the voltage coming from the bulb socket when it's on and off. If it is coming on and off intermittently like the light, then yeah, there must be some discontinuity in the switch or wire. I have no idea how hard it can get, but if it is just a simple loose contact point of the bulb, then it may be fairly easy to fix?
     
  4. em7145

    em7145 Junior Member

    Joined:
    Jul 7, 2021
    6
    1
    0
    Location:
    Washington
    Vehicle:
    2017 Prius
    Model:
    Two
    Did you ever sort this out? I am having the same issue. Don't know how I missed this in my initial search.
     
    Zzz likes this.
  5. Zzz

    Zzz Junior Member

    Joined:
    Dec 9, 2022
    3
    0
    0
    Location:
    USA
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    I too have been having the same issue on my 2017 Prius Prime Advanced for about 6 months. It is not a loose or malfunction bulb because both dome bulbs will turn on when I manually turn it on.
    With the door in the proper setting, the interior lights are supposed to turn on when the door opens. If I have the door open and push on the dome panel around the switch, I can make the lights go on.
    Is the switch replaceable or is this only available by replacing the entire front dome?
     
  6. jlhopes

    jlhopes New Member

    Joined:
    Oct 23, 2022
    4
    0
    0
    Location:
    Canada
    Vehicle:
    2017 Prius
    Model:
    Base
    I have the same issue in my 2017 Prius. The bulbs themselves work fine when I turn the switch to the "on" position. But when it is in the middle, on "door", the lights do not come on automatically as they should. Twice now I have pried off the cover, pulled out the switch and cleaned it off. When I put it back in, everything works as it should for a time, and then it stops working again. So, it would appear that the connection is getting shaken loose somehow.

    If anyone has had this fixed or knows how to fix it themselves, I would love to know about it! It's hard to believe that in 2022 something as simple as a light switch is failing.
     
  7. CurtisKNC

    CurtisKNC New Member

    Joined:
    Jan 20, 2023
    2
    0
    0
    Location:
    Raleigh, NC
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    I have a 2017 Prius Prime. Same issue. It comes and goes. The fix is replacing the map light assembly. The part lists at $200USD, but ordered online from Toyota is closer to $129. You need a device like a trim puller, which is a mini-pry-bar. You pull the assembly off, unplug it, pipe it back on. Piece of pie. There are videos on the web.​
     
  8. Will Bradley

    Will Bradley Junior Member

    Joined:
    Jun 23, 2015
    3
    2
    0
    Location:
    USA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    You can actually do some maintenance on the switch itself, I followed a procedure on the youtube video with ID# ETv0WX4BsX0 (can't post links sorry) and also squeezed the contacts a little to apply more pressure, and replaced the dielectric grease. For $198 cheaper it's worth a try.
     
  9. Zed Ruhlen

    Zed Ruhlen Active Member

    Joined:
    Sep 2, 2018
    230
    122
    0
    Location:
    Hood River, OR
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    I have the same issue with my 2018 PP. Sounds like an engineering problem with this design. Has anyone figured out how to fix the switch rather than replace it with one that will also fail?