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Power window motor & afterthoughts

On a 2000 Toyota 4Runner Limited:



On my first visit to the Toyota dealer I was told I needed a relay to make the lift gate power window operate. So I ordered it, installed it, but did not get an operating window. On the second visit they took back the relay and told me what I really needed was a new motor. The old one drew too much current to make the window operate. So I ordered the motor and left. The afterthought was - why does the motor draw too much current? Is all the window really need is some friction reduction? So I ask this here before I go back in and start messing with the mechanics of the window. Is it useful to try to clean up the tracks or whatever other mechanics are in there?



Thanks.



George

Yes, it’s worth a try before you spend more money.

Put silicone spray into the window track and see if it helps. Use the little straw that comes with it or you will have a big clean-up job.

Can you feel initial activity from the motor before it shuts itself off due to the suspected over amp condition or is there no indication that the motor even trys to work?

Excessive current results from either an excess load on the motor or an excess load internal to the motor…as in a binding bearing or something similar. However, excess current should also pop a fuse. Which leaves me wondering…did they measure the current draw or just guess, like they did with the relay?

I say try cleaning the tracks. Also try cleaning and lubing the regulator assembly. Also check for voltage to the motor. If you have clean tracks, a clean and oerating regulator assembly, and voltage to the motor, and no operation, you need a motor.

Does the hatch need to be closed for the window to operate? If so it could be a bad safety switch in the door jamb.

Has the dealer shown you the wiring diagrlam for this circuit?

A damaged electric motor, whether due to binding or an internal short, can draw a lot of current without even moving. This happens a lot with starter motors on cars, but can happen to any electric motor of any size. There’s not a lot to this system. if the motor’s getting power but not moving, the motor is bad. A lot of cars have circuit breakers that automatically reset when they cool down for the power windows. So this may be why you’re not blowing a fuse. A simple quick n’ dirty test for whether the motor is getting current is to turn on your headlights at night without the car running, hit the window switch and see if they dim any. These motors draw a lot of current anyway, so you will usually notice some change in the brightness if the motor is getting current whether or not the window is moving.

Thanks for the replies.

Well, even replacing the motor didn’t help. I had the regulator detached from the window and tried running it - no luck. I don’t know how much force it should take to move the regulator, but I was certainly able to move the arms with the application of some force. Pure guesswork: 5 ft lbs. maybe. So I’m stumped.

Sounds like you may need an new regulator (which should come with the guide tracks inside the door). If your regulator has cables and pulleys like on my truck, they wear and start to bind. Sometimes the motor comes with the regulator (it could be riveted in like mine).

As it turned out, the answer was none of the above. There was a faulty ground in the wiring. So I got to pay restocking fees on a motor and a regulator. But I still think I came out ahead - they most likely would have left installed the relay, motor and regulator to create a $1,000 window repair job.

Thanks again for all the replies.

George