Tail gate on 2004 Envoy XUV

check the fuse/relay. if it is neither of these check the switch with a multimeter. If you can hear the motor trying to move the glass when you try the switch it may be the regulator needs attention. It may be the motor needs to be replaced.

check fuse and relay along with the switch first then the regulator and motor afterwards. Replacing the small electronics is obviously easier than having to open up the tailgate to check the mechanics of the winedow.

Dealer or a junk yard

this is the exploded view of tailgate https://www.gmpartscenter.net/v-2004-gmc-envoy-xuv--sle--4-2l-l6-gas/body--tailgate this is removal and working on an xuv https://www.youtube.com/watch?v=MLQLAD8xOPk

do you have the tailgate with the window in the upper half and does the window open?

Do you live in a dusty area? My sister lives in dusty New Mexico and had a malfunctioning XUV tailgate. My reasoning was that something must tell the tailgate not to drop down if the glass is up, and if it can't tell, then it will only open sideways.
So we removed the trim panel, and the tailgate was indeed full of dust. By reaching my arm in, I found two plastic optical sensors which tell the gate whether the glass is up or down; both were coated with dust. After cleaning these the tailgate was back to its normal operation. The two sensors are flat, round - about the size of a nickel or dime...I couldn't see them, just found them by guessing that they must be there. Hope this helps!

Not without a LOT of trouble. Your pretty much hosed.

pull the plastic off of the tailgate and make sure the small wire looking controls are still hooked up. sometimes they will pop out after alot of use. other thing is make sure the rear actuator is actually working (it could be bad)

The tools are under the second row seats. The hole for the spare tire lowering mech. is above the rear bumper when you lift the tail gate. Put the proper tool down the hole, turn counter clockwise, lowers spare. Reverse to bring up.

I also have a 2004 GMC XUV. My gate would go down but not swing open. In trying to fix it, the gate then refused to go to the flat position.I have removed the cover plate on the gate and found the one of the solenoids loose from its mounting. Resetting the computer by disconnecting both battery leads and holding them together for ten seconds worked to restore function to the gate going flat, but the swing still does not work. I believe it is a bad solenoid or motor for the bottem left latch pin.

the actuators have a white stem that sticks out of the bottom of them. if you push up on the ones on the driver side it will open the back hatch for you.