1. Check the Obvious:
* Battery: This is the most common cause. Check the battery terminals for corrosion (green or white buildup). Clean them with a wire brush and baking soda solution if necessary. Then, check the battery voltage with a multimeter. A voltage below 12V indicates a weak or dead battery. If the voltage is low, you might need to jump start it or replace the battery.
* Fuses: Check the fuse box (usually under the hood and/or inside the car, near the steering column). Look for blown fuses (a broken filament inside the fuse). Replace any blown fuses with the correct amperage rating. A blown fuse could indicate a short circuit somewhere in the system.
* Lightswitch: Make sure the lightswitch itself is turned on. This might seem obvious, but it's an easy thing to overlook. Try turning the switch multiple times.
2. If the above doesn't work:
* Alternator: A faulty alternator can't charge the battery. While your lights might come on initially, they'll likely dim and eventually go out. This will usually be accompanied by other electrical problems. You'll need a multimeter to test the alternator's output voltage while the engine is running.
* Wiring: A damaged wire or loose connection somewhere in the system could be interrupting the power to the lights. This is a much more involved problem requiring a visual inspection of the wiring harness. This is best left to a mechanic unless you have experience with automotive electrical systems.
* Body Control Module (BCM): The BCM controls many electrical functions in the car. A malfunctioning BCM could cause multiple electrical problems, including the lights going out. This is a complex issue that requires professional diagnosis and repair.
* Ignition Switch: In some cases, a faulty ignition switch can prevent power from reaching the lights, even when the key is in the "on" position.
Important Safety Note: Never work on the electrical system of your car while it's running. Always disconnect the negative battery terminal before doing any work.
What to do next:
* If you're comfortable working on cars: Armed with a multimeter and a fuse chart for your specific Pontiac model, you can try troubleshooting the electrical system yourself.
* If you're not comfortable: Take your car to a qualified mechanic or auto electrician. They have the tools and expertise to diagnose and fix the problem safely and efficiently. Describing the issue clearly (all lights out, only headlights, etc.) will help them pinpoint the problem faster.
Don't attempt any repairs beyond basic fuse checks if you're not experienced with automotive electrical systems. Incorrect repairs can be dangerous and may cause further damage.
