The 2003 Chevrolet Silverado is a member of the first generation of Chevy’s full-size pick-up line that replaced the C and K models. It is also the counterpart to GMC’s Sierra. The two truck lines closely resemble each other and share many parts, which lowered design, inventory, and acquisition costs. This generation lasted eight years, introducing many model, trim and engine options. These options include the 1500, 2500, 3500, Heavy Duty, Super Sport and Denali with multiple gasoline and diesel powerplants available.
The 15-amp SBA fuse in your underhood fuse box is for the Supplemental Brake Assist system. This indicates that your truck has vacuum assisted power braking technology. The Supplement Brake Assist system supplies additional vacuum power to the vacuum assisted power brakes when the engine’s vacuum is diminished. This is accomplished by starting a small motor which generates the additional vacuum power. When the supplemental system is activated, you should feel a slight vibration in the brake pedal. It is normal for the system to activate under certain driving conditions. However, if you feel the supplemental system activate every time you apply the brakes, this may indicate a vacuum leak somewhere in the engine vacuum system.
Remove the SBA fuse from the fuse box with a fuse puller. Closely look at the metal filament in the middle of the fuse. If there is a break in the filament or scorching on the plastic housing, replace it with another 15-amp fuse.
