Headlights dim.

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by SoShoreKen, Oct 20, 2021.

  1. SoShoreKen

    SoShoreKen Junior Member

    Joined:
    Aug 29, 2016
    18
    5
    0
    Location:
    South Shore MA
    Vehicle:
    2013 Prius
    Model:
    Persona
    Last month or so my headlights are very dim. One side doesn't seem to even shine straight anymore. High beams and daytime running lights are fine. Just the low beams.

    I replaced the bulbs twice. Last time with brighter bulbs. But they look the same to me. Not brighter. I cleaned the headlight plastic too. No change.

    Anyone have any ideas?
     
  2. Air_Boss

    Air_Boss Senior Member

    Joined:
    Jun 2, 2012
    3,386
    866
    0
    Location:
    New Yawk
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    Any corrosion in the lamp socket or socket connection to 12V power leads?
     
  3. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,013
    2,095
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Assuming you are not getting cheap bulbs online, some of which are dim, I would suspect the sockets.

    While there are ways to check for unintended voltage drops, a good visual inspection of the sockets would be my first step.
     
    Tim Jones likes this.
  4. SoShoreKen

    SoShoreKen Junior Member

    Joined:
    Aug 29, 2016
    18
    5
    0
    Location:
    South Shore MA
    Vehicle:
    2013 Prius
    Model:
    Persona
    What's the best way to clean the sockets? I'll check those when I can.
     
    Air_Boss likes this.
  5. rjparker

    rjparker Senior Member

    Joined:
    Jun 6, 2008
    4,013
    2,095
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    If they are bad they will likely to be damaged. I would cut them out and splice in new sockets with a longer pre-terminated cable for ease of use.

    Another check would be the ground connections. A2 and A3. I would bet on a poor brand or damaged sockets first.
     
    Tim Jones likes this.
  6. Air_Boss

    Air_Boss Senior Member

    Joined:
    Jun 2, 2012
    3,386
    866
    0
    Location:
    New Yawk
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    A fine brass brush or rotary 'pipe cleaner' is ideal to clean the socket electrical contacts, then apply dielectric grease. If they appear to be heat damaged, that is evidence of corrosion and resistance heating, and the socket is not serviceable. It could also be a cut through the 12V power leads. Squirrels and mice have been known to chew on Toyota (and Honda generator, ask me how I know) wire insulation, sometimes right through the conductors. You could use a DVM to measure voltage while wiggling the harness. If it is intermittent, follow the leads visually to inspect them for cuts.
     
    Tim Jones likes this.
  7. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,723
    2,268
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Any kind of wire brush is not good because it can leave "splinters" inside the socket and cause a short.
    And recommending dielectric grease in places like that is not good either because most varieties of it is an insulator and may cause more problems than it solves.
     
  8. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,723
    2,268
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Some voltage measurements need to be taken.
    This could be a sign that there is a problem developing in the 12 V power system; battery, main connections or charging circuitry.
     
    Tim Jones likes this.
  9. Tim Jones

    Tim Jones Senior Member

    Joined:
    Jul 17, 2018
    1,177
    423
    3
    Location:
    SE Texas
    Vehicle:
    2013 Prius v wagon
    Model:
    XLE AWD-e
    Are the bulbs LED?
    Are you sure the plugs are pushed in all of the way and click?
     
    #9 Tim Jones, Oct 20, 2021
    Last edited: Oct 20, 2021
  10. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
    3,459
    1,524
    1
    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    It's possible that you have a poor ground connection at one of the headlights.
     
    Tim Jones likes this.
  11. Air_Boss

    Air_Boss Senior Member

    Joined:
    Jun 2, 2012
    3,386
    866
    0
    Location:
    New Yawk
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    That's why you use a brass brush, and an air duster following the socket cleaning.

    Dielectric grease is specifically designed to seal without increasing resistance on properly mating surfaces.

     
  12. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,723
    2,268
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    NO IT IS NOT.
    There are different kinds and some, the original formulas, are almost perfect INSULATORS.
    If you are going to put it on a conducting surface, you NEED to be sure and get the kind that IS conductive.......or else you are likely to be sorry.
     
Loading...