* Headlight Switch (despite being "good"): While you say the switch is good, it might have a problem specifically with the headlight circuit, not the running light circuit. The switch often has multiple contacts for different light functions.
* Fuses: Check the fuses specifically for the headlights. There might be a separate fuse for headlights even if the running lights have their own. Consult your owner's manual for fuse box layout and which fuse(s) control the headlights.
* Relay: Headlights often use a relay to switch the high current needed. A bad headlight relay will prevent the headlights from functioning. Locate the headlight relay (often in the fuse box or under the hood) and try swapping it with a known good relay of the same type.
* Wiring: Look for broken or corroded wires in the headlight circuit. This is especially true at the connection points near the headlights themselves, the switch, and the relay. Check for frayed insulation, loose connections, and corrosion.
* Multi-Function Switch (often called turn signal switch): This switch controls turn signals, high beams, and sometimes headlight operation. A problem here could prevent headlights from working.
* Headlight Bulbs: Though less likely if running lights work, check the headlight bulbs themselves. They might be blown even if the filaments for the parking lights are still intact.
* Grounding Issues: A poor ground connection can prevent the headlights from working correctly. Check the ground connections at the headlights and the chassis. A clean ground is critical for proper electrical flow.
Troubleshooting Steps:
1. Check the fuses: This is the easiest and quickest first step.
2. Inspect the bulbs: Make sure they haven't burned out.
3. Check the headlight relay: Swap it with a known good one.
4. Examine the wiring: Look for any obvious damage or corrosion.
5. Test the headlight switch: This is more involved and might require a multimeter to check for continuity across the switch contacts. This step is more for confirming a suspected faulty switch.
6. Inspect ground connections: Clean all grounds.
If you're not comfortable working with car electrical systems, it's best to take your Corsica to a qualified mechanic. Improper electrical repairs can lead to further damage or even fire.
