The main fuse box is located in front of the battery box inside the engine compartment. Just be careful taking the fuse box cover off because you can break off the clip which is located toward the drivers side of your truck in front of the negative side of the battery box. Once you take the fuse box cover off, turn it over you will see the diagram where the brake fuse is located. This 20 amp fuse should be located at the #01 location but may differ on your truck. If the brake fuse isn't blown, it could very well be a bad brake light switch. This switch is located behind the upper portion of the brake pedal. If this switch is bad, your cruise control won't work either. This brake light switch replacement is an easy fix. However, you need to adjust the length of the new switch in order for it to work properly. Just use your old switch as a reference to adjust the length of the plunger on the switch. I hope that this helps you figure out what is wrong with your truck.