The pivot can be wear out, or the linkage may be broken. The linkage may be hard to access, but look carefuly to find how to access to it, some bolts are located, well hiden, under the hood.
I'm assuming its like other buick regal models, around the passenger side windshield wiper.
2000 buick regal wiper pulse board /timing wipers
fuse for windshield wiper motor for a 1995 buick regal
I have a 1999 Buick Regal GS and the cabin air filter is located under the hood on the passenger side on top of the firewall near the windshield wiper. The cover has screws holding it down.
Open and read your owner's manual. The location is listed there. You have to remove the plastic trim around the passenger side wiper. It is under the window.
The 2003 Buick Rendezvous takes a 24" drivers side, 22" passenger side and a 16" rear wiper. See sources and related links below for more information. Since there are over 22 different wiper arm attachments, do not buy wipers just by length only. Be sure to lookup exact wiper blade part numbers by vehicle make, model and year for the brand wiper you decide to purchase. This ensures correct length AND correct attachment.
The 2010 Buick LaCrosse takes 26" drivers side and 18" passenger side wiper blades. See related links below. Length is not the only issue when purchasing wiper blades, so is attachment. Always lookup exact wiper blade part numbers by vehicle make, model and year.
In the engine compartment passenger side.
pull it and switch it with your wiper relay or a similar same part numbered one.
The 1998 Buick Regal wiper blade sizes are 22" wiper blades on both sides front. See sources and related links below for more information. Since there are over 22 different wiper arm attachments, do not buy wipers just by length only - be sure to lookup exact wiper blade part numbers by vehicle make, model and year for the brand wiper you decide to purchase. This ensures correct length AND correct attachment.
Check your wiper linkage under the hood and/or the tightness of the wiper arm on the wiper spindle.
The windshield wiper relay is under the dash on the drivers side of the passenger compartment.