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Tuesday, May 10, 2011

1999 Toyota Sienna Wiper Repair...


Temporary Note for the month of October:  If you find the post below useful please consider purchasing a round of popcorn from the link above for yourself , for the scouts and my son who's idea it was to put this on polifrog. 

The family's Toyota Sienna's intermittent wipers became intermittently operational while traveling the National park circuit almost two years ago. Coincidently the slow setting would fail as well as the the "auto home" feature common on all autos today. Good timing was required when turning the wipers off otherwise the wipers would likely stop mid windshield. The only settings that worked consistently were the off setting and the high setting. Good enough ... ignored.

Well, it was ignored until a couple of months ago when we were increasingly reduced to one wiper setting ... off.

The wiper motor seemed fine so I was initially interested in hunting down the only the control relay. As it turns out a little research lead me to conclude that the relay is integrated with the wiper motor itself. With that knowledge and after a visit to car-part.com a fifteen dollar replacement wiper motor was in hand.

The replacement motor replaces the one tucked behind the air filter housing. Two mounting screws are easily reached from the front; the other two are hidden from sight but easily located as they are near the wiper arm pivot points.

Before removing the wiper mechanism, though, the wiper arms must be removed from the assembly. A plastic cap covers the nut that holds the wiper arms to the conical splines of the wiper mechanism. Occasionally these nuts work loose striping the spline pictured to the right and requiring the replacement of the entire wiper mechanism. Be wary during reassembly.

With the wiper mechanism (sometimes referred to as a transmission) off of the van one can scribe the position of the arm that is attached directly to the wiper motor. Perhaps this is an unnecessary step as a miss-match can be corrected for when reattaching the wipers, but I prefer to keep things as originally designed.

With the position of the drive arm marked and the drive arm removed the motor is easily removed from the mechanism. Once the new motor is bolted in place the scribing done earlier facilitates positioning the drive arm on the motor's spline. As a secondary conformation of the proper position of the drive arm I connected the motor to the van's wiring and ran the wiper mechanism while laying free.

I first ran it on intermittent. Note that the arm stops on the scribe:

I also ran it on low and high:

And finally tried it out on the van:

For those interested, out of curiosity I took the old wiper motor apart. Removing the cover revealed the failed electronics that control speed, intermit, and wiper stop. There was also some corrosion that was most visible on the inside of the plastic lid as though the motor had been splashed with salt. Under the electronics was the worm gear that ran the drive arm.



  1. Fantastic post, very thorough! Following your analysis of the old motor, do you think it could be repaired? If so, would you have repaired instead of purchasing a replacement (knowing what you know now)?


  2. Nah, not at $15 for a replacement.

    Additionally, the control module does not lend itself to disassembly.

  3. Yeah, that's about what I figured.

    I need to tackle this on our Camry. The motor must be hidden in the same chamber as the wiper transmission. I imagine it's not so different, overall, than your job. Any advice for getting into that chamber safely and without breaking anything?

    Looks like the cheapest motor for my application is $25. They had cheaper ones during the summer. I'm amazed at the price range on these items.


  4. Your motor is easier to change that the Sienna description above.

    The motor is mounted directly to the firewall. It is on the left side at the back of the engine compartment just below the windshield.

    There are 3 or 4 10mm bolts that hold it to the fire wall. Unfortunately that is not all. There is one more under the cowling. This is the plastic piece under the windshield. The windshield wiper pivots poke through it. It will easily snap off. Access to the remaining bolt is through the revealed opening. i believe it is a 12 mm. Once the nut is off the spline may not let go easily. Jiggle it.

    Before mounting the new motor plug it in and make sure it works. Make sure it has turned off before you turn off the car so that the motor in in its off position. Mount it. As you put the hidden nut on again make sure the wiper arms are in their proper off position. If they are not when the motor is once again turned on the wipers may hit the frame or the fire wall every time they wipe. If they do simply reposition the wiper motor spline on the transmission and retighten the hidden nut.

    Good luck.

  5. Hello,
    I have a 1998 Camry. I am looking to buy a windshield wiper motor. I called my local auto recyclers to check on buying a used part and they said he needed to know which manufactorer build my original motor (which you'd have to open motor housing to see). Do you know if that is a requirement? I looked at the site where you purchased your's and I don't see any mention of a manufactorer.

  6. Thank you for the information! I'll give it shot. Is there anything I need to be aware of (or any trick) to unsnapping the plastic cowl cover without damaging it?

  7. One other question...how'd you know on carpart.com which model to choose: Itta-esna mfr or Nippondenso mfr? I don't even know what that means.

  8. No tricks in the unsnapping the cowl.

    On my Camry the motor is visible on the firewall. Look for something that indicates the manufacturer. Chances are that it will be a Nippondenso.

    If you can bring the old motor in with you when buying the replacement and compare them.

    Additionally, when I do a search on Car-Part I narrow it down to my local area first so that the part is local and I can pick it up. Prices sometimes do not allow this approach, though.

    Shipping is always a gamble. I try to avoid it.

  9. Yeah, I emailed a local place through that website and never heard back. Guess I need to make some phone calls...and take a closer look at the unit I'm replacing.


  10. Hi there. Thank you very much for the information. I think I have the same or similar problem as I am more than sure my wipers motor works fine, but the problem is that if I switch on the wipers on Intermittent mode - they start working like on a slow constant mode. If I switch to faster mode they are accelerating etc. I have noticed however that if I start the wipers in slow constant mode after what I switch to Intermittent than the wipers are working just fine. It would have all been good if I only had to switch from constant to Intermittent (even if it is a bit uncomfortable to do so every time) however the main problem is that if I spray the window the wipers can stop at the middle of the window or in some other position different from the lowest standard position. Same happens if I switch the wipers on and try to stop them in a second or two - they stop right at the place where they were during the time of switching off.

    First I thought that the problem is in a relay that became malfunctional because of the humidity in the winter, however it turned out that the relay is inside the motor so it is not just a simple as changing it for a minute or two.

    So does your case was the same or not? As I could not find anywhere a dealer that could offer me a price less than 60-80$ for a used or new one, so I guess I will do my best to fix it up myself and if I cannot will have to replace it.

    I know this topic is rather old, however I would be happy to have anybody with some more experience share an opinion...

    1. Yeah, you'll need to replace the entire motor, as it the regulator that is your problem and it is quite well integrated with the motor.

      try car-part.com

  11. My Sienna 2002 rear wiper just stopped working. Any advise?

  12. My Sienna 2002 rear wiper just stopped working. Any advise?

  13. After checking the fuse and wires leading to the motor, replace the wiper motor. It is cheaper and more likely to fail than the switches inside your van.

    If that does not fix your wipers I would then consider replacing the comboswitchs on your steering column.

    Be careful with the air-bag. Be sure to disconnect your battery first.