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

Prius 2017 prime trunk light not working

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by yoyoman, Aug 2, 2021.

  1. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I have just found out that my trunk light is not working this morning. Checked the bulb and it’s good. Can anyone check which fuse is controlling the trunk light?
     
    #1 yoyoman, Aug 2, 2021
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,675
    39,222
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I’d first try replacing the “good” bulb; they’re a couple of bucks apiece.

    if problem persists you can say “I told you so”, but hey, doesn’t hurt to try, and worst case, you’ve got a spare bulb for future.
     
    #2 Mendel Leisk, Aug 2, 2021
  3. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I did replaced with a new bulb and still not working . Check the voltage and only getting 1V at the bulb connector. .. should be 12V. Now I’m wondering if the trunk release switch is bad??
     
    #3 yoyoman, Aug 2, 2021
    Mendel Leisk likes this.
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,675
    39,222
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Ah ok.
     
    #4 Mendel Leisk, Aug 2, 2021
  5. Hidyho

    Hidyho Senior Member

    Joined:
    Jan 26, 2010
    2,698
    529
    0
    Location:
    Texas
    Vehicle:
    2018 Prius
    Model:
    Four
    Stupid question, but did you check the switch on the light and make sure you didn't accidentally turn it off?
     
    #5 Hidyho, Aug 2, 2021
    jerrymildred likes this.
  6. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I did check the switch.

    For some reason, just not getting voltage with the trunk open up. Any idea how to pop the plastic cover snap onto the composite trunk ?
     
    #6 yoyoman, Aug 2, 2021
  7. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    7,035
    2,790
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Another probably stupid question:
    Do the headlights or parking lights have to be ON for that light to work ?

    Then......before you go to a lot of trouble chasing the voltage, check the ground side.
     
    #7 sam spade 2, Aug 3, 2021
  8. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I have tried to leave the headlight on and opened the truck. Still no voltage. I think I’m going to have to take the panel off. Does anyone know how to pop it open?


    Another thing I have tried. I have my POS voltmeter probed at the bulb connector (plus side) and NEG probed to the body. I’m getting 12V. Seem like there is a switch is not working.
     
    #8 yoyoman, Aug 3, 2021
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,675
    39,222
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Wouldn’t you see no volts, if there was a problem?
     
    #9 Mendel Leisk, Aug 3, 2021
  10. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Seem like the pos wire is getting 12v at the connector but the neg wire is not grounded.. it’s weird.
     
    #10 yoyoman, Aug 3, 2021
    Mendel Leisk likes this.
  11. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,675
    39,222
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Ah, gotcha, no continuity between neg wire and car body. Could be the smoking gun.


    (First read of your last post, I thought “pos” was an acronym. :ROFLMAO:)
     
    #11 Mendel Leisk, Aug 3, 2021
    burrito and yoyoman like this.
  12. burrito

    burrito Active Member

    Joined:
    Jul 25, 2021
    274
    114
    0
    Location:
    California
    Vehicle:
    2015 Prius
    Model:
    Two
    You just now made realize that it wasn't!
     
    #12 burrito, Aug 3, 2021
    Mendel Leisk likes this.
  13. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    7,035
    2,790
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    No, it sounds like a GROUND is not working.
    Or that it operates from a switched ground and not switched positive.
     
    #13 sam spade 2, Aug 4, 2021
  14. road2cycle

    road2cycle Active Member

    Joined:
    Jan 18, 2021
    168
    109
    0
    Location:
    Sonoma County, CA
    Vehicle:
    2021 Prius Prime
    Model:
    XLE
    The trunk light socket assembly pries right out of the side panel (at least that’s how it is on the 2021). Just be careful since the wire harness behind there is fairly short. I would remove the wire harness plug and check it and the light assembly contacts for corrosion/oxidation/loose connections/etc. You could also probe directly across the wire harness connector for 12V with the trunk open to verify voltage is good up to that point.
     
    #14 road2cycle, Aug 4, 2021
  15. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I have taken the assembly out and disconnected. Both male and female connector are like new. Probe the positive and negative at the connector and get no 12v. However, I did get 12v when probing the positive connector side with a voltmeter and probing negative to any car chassis. Seem like the negative wire at the connector is disconnected somewhere.

    I need to find out where is the switch that turn on the trunk light after releasing the trunk.
     
    #15 yoyoman, Aug 5, 2021
    Last edited: Aug 5, 2021
  16. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    7,035
    2,790
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    OR that light works by switching the negative side.
    Almost all of them used to work that way.
     
    #16 sam spade 2, Aug 5, 2021
  17. yoyoman

    yoyoman Active Member

    Joined:
    Apr 19, 2005
    342
    117
    0
    Location:
    San Jose California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I have popped the panel off this morning.

    Wiggle the exposed connectors and found 1 was loose. Took it out and plugged-in back. Then said the magic word “Abracadabra”. My trunk light is back to business again.

    IMG_0741.jpg
     
    #17 yoyoman, Aug 6, 2021
    Mendel Leisk, jerrymildred, dig4dirt and 2 others like this.
  18. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,675
    39,222
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    And it was the connector at the hatch lock, lol.
     
    #18 Mendel Leisk, Aug 7, 2021
(You must log in or sign up to post here.)