To troubleshoot problems with a Chevy truck’s brakes, you must first identify the specific problem. Common problems with brake lights, for example, are due to blown fuses, defective bulbs and corrosion on the light sockets.
Start by checking the fuse block under the dashboard to examine the brake-light fuse and replace it if it has blown. Use a multimeter to diagnose the brake-light switch, and if there is no voltage present, then the switch is bad. Open the tailgate and unscrew the taillight lens to pull it out. Check to see if there is a burnt filament and replace the bulb if necessary.
Depress the brake pedal and wedge it down. Use a multimeter to examine the bulb socket by connecting its black wire to a good ground. Insert the probe into the socket and make sure it touches the bottom terminal of the socket.
On the meter's resistance scale, check to make sure there is zero ohms to ground. If it shows resistance, inspect the wire to the ground and tighten its connection before retrying again. Install a new bulb. If it does not light, the spring contacts in the socket are bent or worn. Replace and test the bulb again.