On my 2000 Toyota Sienna, the driver's side power window behaves strangely. The window rolls down just fine. However, when closing it, it begins rolling up in the normal rate, but half-way up gets slower until completely stops. I then wait some time and able to continue the roll-up some more - and repeat this sequence until it is completely closed.

Basically, you can think of it as if I "charge" the window motor's very "small" battery, which depletes on the way up. Then repeatedly allow it to "re-charge" and get depleted again while gradually rolling up.

What is the cause of this behaviour?

What part do I need to replace/service?

8 Answers 8


Your window motor and/or regulator is going out. What happens is, the window motors have a thermal trip which tells them to stop when they get too hot. As a vehicle gets older, the window regulator and slides don't slide/move as well, so creates a lot more friction. The window motor starts wearing out because of this and more heat is produced, thus shutting down the motor. When it sits for a little while, the motor then cools down, thermal trips back to good, and you can then push the button and the window continues on its way.

  • Thanks. That makes sense. I was not aware of a thermal protection. But, the interesting thing is that it is so now (freezing winter) but was the same last summer. I'd expect the winter temps to make it easier, but it is not so (of course, it is possible that the cold temps increase the friction itself, and that compensates for the heat dissipation).
    – ysap
    Commented Jan 13, 2014 at 19:23
  • So, I should fix the friction problem first, then replace the motor, right?
    – ysap
    Commented Jan 13, 2014 at 19:23
  • You can try cleaning the regulator/tracks, but more than likely motor replacement is your only choice. You can sometimes just replace the motor (much cheaper option, but a lot more work), or motor and regulator together (think of this as the dealership option ... what you'd get from the dealership if you go there to buy it). You should be able to purchase a motor online from rockauto.com or something similar. Just also check to ensure your source is reliable. There are a lot of crap motors on the market. Either way, you'll be doing both at the same time. Commented Jan 13, 2014 at 19:27
  • The thermal fuse issue is real. The thermal fuse trips real fast when the current goes up. The current goes up when friction is high or the motor overloaded for my reason.( Friction could be high in winter and low in summer) .In most Toyota / Lexus it is the thermal trip that turns off the motor when it is blocked from moving.
    – Arjun
    Commented Dec 24, 2019 at 8:22

What I've found in several of these is that the motor itself is fine, but it's internal thermal fuse goes bad (becomes higher resistance giving less voltage to the motor). I've even replaced the thermal fuse for a couple bucks and the motors then work like new. I wouldn't recommend doing this unless you are familiar with soldering and electronics.


I would like to take this time to share my thoughts in regard to the problem I've had with the 2000 Sienna.

I've resently changed the drivers side motor that had the same problem.

Only to have a problem a month later.

My problem was not my motor but instead it was due to the Increase friction.

Also the thermal fuse that is internal becomes very hot and it gets a higher resistance as well as giving less voltage to the motor.

This was causing the motor to turn off.

I found that my problem was that the tracks needed a really good cleaning.

It's probably a good idea to change the internal fuse.

But soldering is not my forte.

  • Hi Walter, welcome to the Mechanics.SE. Thanks for your input on the subject. Surely someone will find it useful, as I already replaced that 2000 sienna.
    – ysap
    Commented Aug 9, 2015 at 17:06

The power window motor is getting hot inside and shuts down. When it cools it starts to work. This is a sign that it is going bad. It is a good idea to replace the window regulator at the same time since the regulator will have to be removed to replace the power window motor. Also put extra grease on all moving parts.


The power window motor is getting hot inside and shuts down. When it cools it starts to work. This is a sign that it is going bad. It is a good idea to replace the window regulator at the same time since the regulator will have to be removed to replace the power window motor. Also put extra grease on all moving parts.

  • I have no idea of what you speak is true, but it's a super excellent answer. Welcome to mechanics.stackexchange.com I hope that you become a regular contributor. (2010, 2014, 2018 Sienna owner)
    – SteveRacer
    Commented Oct 14, 2018 at 6:06

The purpose for the thermal protector is to provide a means to shut down the window motor in the event a child or even an adult has his hand in the open window while it is moving. These tiny protectors are located inside the motor and they sense the amperage going through them. When a motor binds slightly, the amperage rises sharply and this increase in amperage heats the thermal switch next to it and opens it. Out side temperature has very little effect on this since it is inside the motor and reacts quickly to a sharp rise in temperature.

  • Thanks, and welcome to M.SE. That's a great explanation.
    – ysap
    Commented Aug 26, 2019 at 16:31

To all who say the motor is getting hot;

When the wether is -30c, the window will only go down maybe a cm. When I park in garage car warms to +20c. The window now goes down fully and quickly when temperatures are 50 c degrees warmer.

How does the motor get "too hot" overnight in temps extremely cold but "cools down" when room temp or even extreme heat?

To me this discredits everyone's proposed solution. Without knlwing cars, it seems like a "pressure/vacuumed" related issue. A closed air system when cooled will decrease pressure. Also a colder material has less friction than the second material with exception of only water. Substances expand when heated and contract when cooled, thus surface area decreases when colder and thus friction is reduced. Again, this refutes suggestions of friction increase in colder temps.

  • The original poster doesn't mention anything about the ambient temperature, so we have to assume they were testing it in consistent conditions. It sounds like you're having a different problem, so it would be better if you were to ask a new question (please use the ask question link at the top), giving as much information as you can about your car and the conditions you're having problems with.
    – Nick C
    Commented Jan 30, 2019 at 9:52

I had a similar problem on a 2000 GMC Sierra passenger window. I cleaned the window tracks and then sprayed them liberally with arousal silicone lubricant. And in this case removed the window tint film as portions had been scraped off leaving a very rough surface that was causing much friction at the "squeegees" that clean the glass as the window travels down into the door. I bought a brand new regulator with motor for the driver side from eBay for $21. Couldn't believe it works great and while the motor was a bit smaller than oem, materials and build quality are decent.

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