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Keep blowing door lock fuse

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by roostercruiser, Jan 28, 2016.

  1. roostercruiser

    roostercruiser Junior Member

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    I have to manually lock my car doors, and use the door handle unlock sensor to open them. If i use the key FOB or power lock button it blows the fuse. Would the power lock switch on door panel make the fuses to blow or could it be something else?
    I would like to lock my rear hatch, locking the car the way i do i can never lock the rear.

    It only blows when locking and does not blow while unlocking.
     
    #1 roostercruiser, Jan 28, 2016
    Last edited by a moderator: Jan 28, 2016
  2. valde3

    valde3 Senior Member

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    Does it also plow the fuse if you use fob to unlock the doors?

    If not then (if I did get this right) it plows the fuse every time you try to power lock it but works fine when you power unlock it. In that case maybe the lock wire going to some door (trunk doesn’t have lock wire) is grounded. If your car hasn’t been on accident most likely place is where wires go into the door.

    If that’s not the case then please verify when does the fuse plow?
    Interior lock switch?
    Interior unlock switch?
    Fob lock button?
    Fob unlock button?
    Exterior door lock button?
    Exterior door unlock pad (inside of door handles)?
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Something else. To be specific, either the body ECU itself, which provides power to the lock motors; or one of the four door lock motors has a problem. The hatch lock motor is not the problem because it only unlocks.

    If you want to be systematic about the troubleshooting, you will obtain the electrical wiring diagram and pin out info for the body ECU from techinfo.toyota.com

    You will also need a 12V power source and an ammeter.

    Then you would identify the body ECU wiring harness connectors that feed the four motors. The two right hand side motors apparently are powered via the same body ECU pins so they will take 2x as much current as the left hand motors which are individually fed.

    The left hand motors are individually fed because there are occasions when the body ECU only wants to unlock the driver's door and leave the other doors and hatch locked.

    You would apply 12V to the motors, one at a time, with polarity so that the doors lock. If they unlock then reverse the polarity.

    See if a motor draws much more current than the others, keeping in mind that the two on the right when combined obviously will draw 2x the current of individual motors on the left. If so, that door lock motor needs to be replaced.

    If you find that the four lock motors behave similarly, then the body ECU probably would need to be replaced.
     
    #3 Patrick Wong, Jan 29, 2016
    Last edited: Jan 29, 2016