1. Check the Bulbs:
* Access the Bulbs: Locate the brake light bulbs in the rear taillights. You'll likely need to remove the taillight assemblies themselves. This usually involves unscrewing some nuts or bolts holding the assembly in place. Refer to your owner's manual for specific instructions.
* Inspect the Bulbs: Carefully remove each bulb and visually inspect the filament. A broken filament will be clearly visible. If it's burned out, replace it with a bulb of the correct wattage and type (check your owner's manual or the old bulb).
* Test the Bulbs (Optional but Recommended): Before reinstalling, test the new bulbs in a working light socket to ensure they are functioning.
2. Check the Fuses:
* Locate the Fuse Box: Consult your owner's manual to locate the fuse box (usually under the hood or under the dashboard).
* Identify the Brake Light Fuse: The owner's manual will also show which fuse(s) are for the brake lights (often labeled "brake," "stop," or similar).
* Inspect the Fuse: Carefully remove the fuse and check for a blown filament. A blown fuse will have a broken internal wire. Replace any blown fuses with fuses of the correct amperage (printed on the fuse itself).
3. Check the Brake Light Switch:
* Locate the Brake Light Switch: This switch is usually mounted on the brake pedal assembly. It's a small, usually cylindrical switch that's activated when you press the brake pedal.
* Inspect the Switch: Visually inspect the switch for any damage. You might need to reach under the dash to access it. Sometimes they just wear out.
* Test the Switch (Requires a Multimeter): This requires a multimeter. Disconnect the switch and use the multimeter in continuity mode to test if the switch closes when you depress the brake pedal. If it doesn't, the switch needs replacing.
4. Check the Wiring:
* Visual Inspection: Carefully examine the wiring harness leading to the taillights for any obvious damage, fraying, or loose connections. Pay particular attention to the area near the brake pedal and where the wires enter the taillight assemblies.
* Continuity Testing (Requires a Multimeter): If you suspect a wiring problem, you can use a multimeter to check the continuity of the wires from the switch to the bulbs. This is more advanced and requires some electrical knowledge.
5. Grounding Issues:
* Poor grounding can cause intermittent or complete failure of the brake lights. Check the grounding points at the taillight assemblies and ensure they are clean and secure.
Important Considerations:
* Safety First: Disconnect the battery's negative terminal before working with any electrical components.
* Owner's Manual: Your owner's manual is your best friend for specific details about your Blazer's electrical system and fuse box layout.
* Professional Help: If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic. Incorrect wiring can cause significant problems.
By following these steps systematically, you should be able to identify and fix the problem with your '94 Chevy Blazer's brake lights. Remember that safety is paramount; if you are unsure about any step, consult a professional.
