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2012 Aqua headlight adjustment dial not working

Discussion in 'Prius c Main Forum' started by ClarkeNZ, Dec 27, 2021.

  1. ClarkeNZ

    ClarkeNZ New Member

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    Vehicle:
    2012 Aqua
    Model:
    N/A
    Hi. I have a 2012 Aqua (RHD, JDM model) and the headlight adjustment dial (right of steering column, next to wing mirror adj controls) doesn't work.

    It's connected behind the dash.

    All the fuses meter out ok.

    I found the proper toyota interactive wiring diagram online and it's been most informative but there's some things I'm just not following, and some junction boxes seem entirely inaccessible without serious deconstruction of the dashboard.

    I suppose it's plausible both adj motors have failed but I can't figure out how to remove them to check. They certainly don't remove like the bulbs do.

    Anyone have any ideas?
     
    #1 ClarkeNZ, Dec 27, 2021
  2. Elektroingenieur

    Elektroingenieur Senior Member

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    The headlight leveling motor is part of the headlight assembly, which the Repair Manual (more info) shows being removed from the vehicle before it can be disassembled. If you have to do this, when reassembling, use a new headlight leveling motor base packing (O-ring, part number 90075-99120).
    That’s probably true, and definitely so for the headlight leveling switch, for which the removal procedure in the Repair Manual says to begin by removing the upper instrument panel assembly.
    If you haven’t already, make sure the tail lights and clearance lights work, which confirms that the TAIL relay and fuse are good and that there’s power at the bus formed by terminals 16 through 22 on junction connector A50.

    You could continue according to the Problem Symptoms Table in the Repair Manual, but to avoid taking the instrument panel apart just to inspect the headlight leveling switch, you might consider checking first in the middle of the circuit, at the instrument panel junction block assembly, the connections shaded in gray on the System Circuit pages in the Electrical Wiring Diagram.

    I think this junction block should be accessible after removing only the glove compartment door assembly. With the taillights on and connector 3C in place, carefully backprobe terminals 23 and 24 (green wires), and confirm that the voltage between each of those terminals and body ground varies as the headlight leveling switch position is changed. If not, the trouble could be in the wiring, but it’s more likely in the headlight leveling switch (part number 84152-52130, now 84152-52131).

    If the leveling voltage is good at 3C-23 and 3C-24, see if you can reach connector A13 or A14 for the right or left headlight leveling motor, respectively, and test again there for leveling voltage, power, and ground.
     
    #2 Elektroingenieur, Dec 28, 2021
  3. sam spade 2

    sam spade 2 Senior Member

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    Any chance that it has been "disabled" on purpose due to local regulations in your country ?
     
    #3 sam spade 2, Dec 28, 2021
  4. ClarkeNZ

    ClarkeNZ New Member

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    Vehicle:
    2012 Aqua
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    N/A
    Mate, thanks ever so much for your detailed reply. You've definitely given me a few things to go on.

    Nice one.

    C.



     
    #4 ClarkeNZ, Dec 28, 2021
    Elektroingenieur likes this.
  5. ClarkeNZ

    ClarkeNZ New Member

    Joined:
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    Location:
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    Vehicle:
    2012 Aqua
    Model:
    N/A

    Hiya... yeah I did wonder that too but I'm sure I've driven cars with that feature here in NZ. My main reason for doing this is because right now they're set in what I would imagine is the low position. Night driving on the open road is trickier than it ought to be. Full beam is full on nuclear. If I can't figure it out I'll do it manually.

    Thanks.
     
    #5 ClarkeNZ, Dec 28, 2021
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