Power window goes down whenever car is started. While it's going down, the power button will not stop it. After the window is down, and after repeatedly pressing the power window button, the window will go up. Once up, it will not go back down with the button.

GET INSIDE THE CAR AND CLOSE ALL DOORS.SWITCH IGNITION ON.USE BOTH UR HANDS TO {AT THE SAME TIME} LIFT ALL 4 WINDOWS UPHOLD THE BUTTONS UP UNTILL ALL WINDOWS ARE UP.RELEASE AND HOLD UP AGAIN.REPEAT AT LEAST 4 TIME .THEN U PUSH ALL 4 BUTTONS DOWN!!!HOLD THERE UNTIL ALL 4 WINDOWS ARE DOWN . REPEAT STEP AT LEAST 4 TIMES!!!SWITCH IGNITION OFF AND ON.U NOW HAVE THE COMFORT BACK!!!!LET ME KNOW IF U STILL HAVE ANY PROBLEMS!!

Is it just one window? Drivers side?

Try & spray WD40 or a similar lube into the window channel on both ends of the glass, It may have just needed lubrication. It also may be a tired motor or faulty switch.

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The regulator maintains (or regulates) the position of the glass as it goes up or down. The power window motor works less going down because of the weight of the glass, whereas going up if the motor's weak, it'll slow going up and will usually overheat and stop while raising the window if its in need of replacement.

It may be a bad Power Window Switch, if the Power Window Motor goes up and down when you ran power leads to it but doesn't work with the switch, than the switch is bad. Replace the power window switch and it should work fine.

The only wiring schematic I could find for your car is for the 2000 Buick Regal, but I hope this helps,
since it gave me a reason why starting a car would cause the driver's power window to
go down, and no other window in the car - it has a special circuit component
(the "Express Down Module").

Its possible that the Express Down Module in the power window switch circuit has failed. This
module latches the "Express Down" switch in the "made" state until released by the "Express
Down Module." If the Express Down Module is latching the Express Down switch when it
shouldn't (at power-up) instead of when it should (at the window "down" limit), then the driver's
window would lower when the driver starts the car. The way to tell if this is the problem is to
note how fast the driver's windows goes down - if it goes down ALL THE WAY, then you know
that the "Express Down" circuit is involved (and therefore suspect the Express Down Module).
If the driver's window only lowers part of the way, then the Express Down circuit is exonerated.
See the various components of the driver's power window circuitry in the
2000 Buick Regal power window circuit schematic below.

I am not exactly sure on this model but most of the time the power windows on the front doors go down all the way. I would check the right passenger side door if it goes all the way down, then most likely the drivers side door should also. Usually the rear windows go down and stop an inch from being all the way down. Some cars are set up to lower the front windows only an inch then by pressing the window down button again, they will continue to roll all the way down.

Probably a fuse or a relay..You can find location of these in your manuel..

Rate well ;o)

the power window motor is bad if you let it sit for a few minuites after it stops you can push the switch and it will start moving again

Spray silicone (lots) down along the guides (where felt is ) at the ends and see if that doesn't help. Try to work it up and down a few times.