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Wiper motor query

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by 1980s_john, Nov 15, 2018.

  1. 1980s_john

    1980s_john Junior Member

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    I have a problem with my Gen III Prius front wiper (car is 2009, 155k miles). The intermittent and low speed settings have stopped working (were juddery last week, completely dead this week), high speed setting still works fine. I had a look at the PDF from this forum, shows the wiper motor has two inputs (12V from battery), one for low speed, one for high speed. I am assuming the low speed is broken on the motor.

    Please can other forum members confirm the part number for a RWD wiper motor (maybe the same for LHD), eBay has one on sale with part number 85110-47200.

    Thanks,
    John
     
  2. ChapmanF

    ChapmanF Senior Member

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    I would try bringing some twelve volt goodness directly to the wiper motor to see what happens, before assuming the motor is at fault.

    Also, here in the US, the bearings in the passenger side wiper arm (the one with funky extra joints) can get stiff and respond well to some light lube. But the last time I looked at the RHD windscreen, it looked as if you guys don't even get a jointed wiper arm like we do.

    -Chap
     
  3. 1980s_john

    1980s_john Junior Member

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    Finally got wipers fixed today, it was a faulty wiper motor. The old motor (from 2009) has a part number 85110-47110. The replacement motor came from a breakers yard from a 2014 model and has part number 85110-47190 (cost me £90 with linkages). All three parts look identical to my untrained eye.

    I have the faulty part to look at, but I made some notes from the working motor for future reference. It has a five pin male socket, pins arranged as follows:

    3 2 1
    5 4

    Pin 5 connects to the metal chassis. Resistance readings were:
    Pin 5 to pin 4 = 4.2 ohm
    Pin 5 to pin 3 = 5.6 ohm
    Pins 1 and 2 are shorted together.

    I didn't try applying 12V before handing it over to my local garage (who diagnosed a faulty motor last week) for a swap.

    hope this helps,
    John
     
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  4. 1980s_john

    1980s_john Junior Member

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    Apologies for long delay in updating this thread. I took the old faulty motor apart, and believe the problem was due to worn out carbon brushes. There are three small square section spring-loaded brushes, that have tags that are soldered to the connecting wires. These all look very worn, with almost no further travel. You can access the brushes by undoing two bolts on the motor housing, this pulls out with the rotor. I expect any decent automotive electrical repair shop would be able to fit new brushes quite cheaply, assuming these are fairly standard size.

    wiperbrush.JPG

    Regards,
    John
     
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  5. seulnom

    seulnom New Member

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    John

    I have the same problem with a RAV4 Wiper motor.

    Re your notes: -
    Pin 5 connects to the metal chassis. Resistance readings were:
    Pin 5 to pin 4 = 4.2 ohm
    Pin 5 to pin 3 = 5.6 ohm
    Pins 1 and 2 are shorted together.
    I didn't try applying 12V before handing it over to my local garage (who diagnosed a faulty motor last week) for a swap.

    Not being an electronics genius can you tell me simply how to test it by connecting a 12v circuit to what pins to test both speeds.

    i.e. negative to pin 5 - and positive to pin 4 for high speed then
    negative to pin 5 - and positive to pin 3 for low speed?

    Also I cant seem to locate a good source of brushes at that size. any hints?

    Thanks in anticipation of your help

    Mike
     
  6. oasmith

    oasmith Junior Member

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    Yep, same problem here, worn out carbon brushes. Any luck on finding replacement carbon brushes instead of buying a whole new motor? I might just go to a salvage yard and scavenge out a motor.