To find the relevant fuses, you'll need to consult your owner's manual. It will have a diagram showing the fuse box layouts and which fuses control the blower motor, the AC compressor (if equipped with an electrically-controlled compressor), and other related components.
Without your owner's manual, I cannot provide specific fuse locations. Looking for a diagram online specific to your 2005 Buick LaCrosse might help, but always defer to your owner's manual as the most accurate source. Incorrectly replacing fuses can cause further damage.
