Assuming that you mean "wiper blade" (blade and frame) which are replaced often rather than "wiper arm" (piece from the spindle at the hood to the wiper blade) which are rarely ever replaced, 2004 Buicks will have various attachments. You'll have to determine which attachment you have by looking at them. Then see the Sources and Related Links section below for installation videos.
Assuming that you mean "wiper blade" (blade and frame) which are replaced often rather than "wiper arm" (piece from the spindle at the hood to the wiper blade) which are rarely ever replaced, the 2005 Jaguar XKR has the most common hook-end wiper arms. See sources and related links below for installation videos. Also, purchase the replacement blades first and there will be additional instructions/illustrations on the replacement packages. Locate and press the tab or button where the wiper blade is inserted into the hook of the wiper arm and pull wiper blade out of hook. You may have to rotate and flex the blade to make enough clearance for the hook to pass through.
http://letmegooglethatforyou.com/?q=how+to+remove+wiper+arms
To remove the wiper arms from a 1996 Concord, remove the small clip holding them on. Then pull up on the arm.
You will have to remove the wiper arms, then remove the cowl, and then the wiper motor.
How do you remove the wiper arms on 2001 Lincoln LS
remove wiper arms and cowl
how do you remove the wiper arms on a 2002 CRV?
Take off the bolts at the bottom of the wiper arms and you may have to wiggle the arms back and forth to work the wiper arms off.
The wipers are connected to the wiper motor by a system of arms and swivel joints. The wiper arm itself may be loos from the connecting rod or a joint in the system may have come loose. you can remove the cowling to get access to the arms.
remove the cowl & wiper arms (mark location of arms on the windshield). disconnect the battery, Disconnect wire connector at wiper motor & remove the 4 mounting bolts then remove the linkage from motor.
remove the caps at the end of the wiper arms. Unscrew the nut holding down the arm and it should come off.
Remove the wiper arms first. Then remove the torx screws that hold the plastic cowl in place.
# Remove the windshield wiper arms # Remove the cowl cover # Disconnect the electrical connector from the wiper motor # Detach the wiper motor/linkage assembly from the cowl # Remove the wiper motor retaining bolts and remove the motor