1. Verify the New Parts: Double-check that you installed the correct bulbs and fuse. Make sure the fuse is rated correctly and properly seated. Ensure the brake pressure switch is correctly installed and is functioning. A faulty new part is always a possibility.
2. Test the Brake Light Switch (Again): Even though you replaced it, there's a chance the new switch is defective or not properly seated. With the brake pedal released, use a multimeter to check for continuity across the switch terminals. There should be no continuity. When you press the brake pedal, continuity should be present. If not, the switch is the issue (even a new one can be bad).
3. Check the Wiring: This is the most likely culprit at this point.
* Visual Inspection: Carefully examine all the wiring related to the brake lights. Look for any broken, frayed, corroded, or loose wires, particularly at the connection points to the brake light switch, the bulbs, and the fuse box.
* Continuity Test: Use a multimeter to test the continuity of the wiring from the brake light switch to the brake lights themselves. You should have a complete circuit when the brake pedal is depressed. Trace the wires from the switch to each brake light and test continuity at each point. This may require accessing the wiring harness under the dash and near the taillights.
* Ground Connection: Check the ground connection for the brake lights. Poor grounding can prevent the lights from functioning. Clean any corrosion on the ground wires.
4. Check the Brake Light Circuit in the Wiring Harness: This is more advanced and may require a wiring diagram. The harness may have an internal break somewhere.
5. Computer Diagnostics (OBD-II): While less likely to directly show a brake light problem, a scan tool could reveal other issues that might indirectly affect the brake light circuit. It's worth a shot, especially if you have access to one.
6. Consult a Repair Manual: A repair manual specific to your 1995 Oldsmobile Aurora will provide wiring diagrams and troubleshooting steps. This is invaluable for tracing the brake light circuit accurately.
7. Seek Professional Help: If you're not comfortable working with electrical systems or if you've exhausted all the troubleshooting steps above, it's best to take your car to a qualified mechanic. They have the tools and experience to diagnose and repair more complex electrical issues.
Remember safety first! Disconnect the negative battery terminal before working on the electrical system. If you're not comfortable working with car electronics, don't hesitate to seek professional help. Continuing to drive with non-functional brake lights is dangerous.
