Where is the backup light switch located on a 1991 GMC pickup?
The backup light switch on a 1991 GMC pickup is typically located on the transmission case. It's a small switch that's activated by a lever or plunger connected to the transmission's shift linkage. You'll likely need to get under the truck to locate it. It's usually near the top of the transmission, but the exact position can vary slightly depending on the specific transmission type.