Passenger power window in my 2002 GMC denali keeps sliding down

Assuming you have power windows. Had similar problem on 2000 Buick LaSabre. Had to replace electric motor drive assembly inside of door. The motor moves a steel cable around nylon/plastic pulleys. In time the cable cuts into the pulley. Access motor assembly by removing inner door panel. I had to purchase assembly from the dealer ($$$). Digital snapshots as you disassemble will help you reassemble. Job took about 1.5 hours, and I had never done it before.

Yes you do, once it is removed and the weather protection is removed you should be able to see what the problem is
either the drive gear on the motor is stripped or the cable has broken
may also be something simple like a clip has broken
you will find it anyway

i would say the theft module saw the door trying to be open without the door lock or fob first, once the door lock button was pushed it shut down, it new doors were trying to be unlocked in a theft manner, once shut down it needs time to reset or needs to see ignition cycle with key and read chip in key, smart system isnt it, good luck.

the lock should come out of the handle. usually there is a clip holding it in. sounds like its broken and you will need another handle, a locksmith should be able to get another lock and make it fit your old key. The dealer is the only place to get a new handle from as far as I know.

The motor has gone weak on you. It comes as an assembly with the regualtor attached.

On the inside trim, you can remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Remove the clips and screws securing the old window to the arm and slide it out through the top of the door (may need to be maneuvered out)

It is the switch or motor, remove door panel and feel the motor and flick the switch up&down if you feel a click in the motor it is not the switch it;s the motor, motor & regulator is about $125.00 at auto zone $65.00 on-line

i CAREFULLY REMOVED THE PANEL, THE SPEAKER, TAKING PHOTOS ALONG THE WAY (INCLUDING PHOTOS INSIDE THE DOOR WHERE I COULD NOT SEE), AND EVENTUALLY REMOVED THE TRACK WITH THE MOTOR AND CABLE. i FOUND THE PLASTIC MOUNT FOR THE UPPER CABLE BROKEN. AFTER MUCH STUDYING I FOUND THE CABLE SNAGGED ON THE REEL. I CLEARED THE SNAG AND LUBED THE REEL. I DRILLED A HOLE TO ACCEPT THE CABLE END AT ABOUT THE RIGHT DISTANCE , INSERTED A SCREW AND EPOXIED THE SCREW AND END IN POSITION, I HUNG THE ASSEMBLY ON THE OUTSIDE OF THE DOOR , PLUGGED THE SWITCH IN AND TURNED THE CAR ON -- THE TRACK WORKED PERFECT. I REPLACED ALL COMPONENTS, ATTACHED THE WINDOW, REPLACED THE PLASTIC REATTACHED THE LINKAGES TO THE LOCK AND DOOR OPENER. WORKS GREAT. SAVED SEVERAL HUNDRED DOLLARS FOR THE COST OF A COUPLE OF HOURS AND A SCREW AND JB WELD EPOXY.MEMBRANE, REINSTALLEED THE SPEAKER,

You'll need to remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. If needed, you can pull back the weather seal (can't reuse it, but it's not that important) and you will be able to access everything inside the door

ok, there is a triangle shaped cover on the inside of the door opposite of the mirror. use a butter knife or similar tool ( flat screw driver) and pry the cover off, it is held in by 2 clips. with that removed you will see the 2 nuts that hold the mirror on (there may be foam insulation covering the nuts). if yours is power then disconnect the connector first then remove the 2 retaining nuts. make sure to hold the old mirror or it could fall after you take the nuts out. install new one in reverse order. viola! good as new!