* Wiring harness: This is a common culprit. Wires can corrode, break, or become disconnected within the harness running from the brake light switch to the taillights. Inspect the wiring carefully, looking for breaks, chafing, corrosion, or loose connections at both the switch and the taillight assemblies. Pay special attention to areas where the wiring might be subjected to movement or abrasion.
* Ground connection: A poor ground connection can prevent the brake lights from working. Check the ground points for both the taillight assemblies and the brake light switch itself. Clean any corrosion and ensure a secure connection. Sometimes these are hidden within the vehicle's body or chassis.
* Brake light fuse (again): While you've checked the fuse, ensure you're checking the *correct* fuse. Some vehicles have multiple fuses related to the brake lights, perhaps one for each circuit or for different aspects of the brake light system. Consult your owner's manual for precise fuse locations and ratings. Also, a fuse might have looked fine but still be internally broken. Try replacing it with a new one even if it looks okay.
* Wiring connector at the taillights: Carefully inspect the connectors at the taillights themselves. Corrosion or loose connections here are common causes. Try disconnecting and reconnecting them firmly.
* Tail light assembly: If you've only replaced bulbs, consider the possibility of a short in the taillight assembly itself. This is less likely but worth considering if all other checks are negative.
* Central Body Control Module (BCM) or related components: In some vehicles, the BCM controls the brake lights. While less likely in a 1995 model, a malfunctioning BCM or a problem with its communication pathways could be a rare cause.
* Trailer wiring harness (if equipped): If your truck has a trailer wiring harness, a short or fault within it could sometimes affect the vehicle's own brake lights.
Troubleshooting Steps:
1. Detailed Wiring Inspection: This should be your primary focus. Carefully trace the wires from the brake light switch to each taillight. Use a multimeter to check for continuity and voltage at various points along the wiring.
2. Ground Check: Thoroughly clean and inspect all ground points. Use a multimeter to test the ground connection for proper continuity.
3. Multiple Test Light/Multimeter Use: Use a test light at the brake light switch to verify power is present when the brake pedal is depressed. Then trace the power along the wiring to the taillights with the multimeter, verifying power at each point.
If you're not comfortable working with car electrical systems, it's best to take your Silverado to a qualified mechanic. Incorrect electrical work can cause further damage.
