* Shorted Bulb Socket: This is the most common cause. A corroded, damaged, or wet bulb socket can create a short to ground. Inspect both sockets for corrosion, melting, or damage. The wires inside the socket might be touching the metal casing. Replacing the sockets is often the solution.
* Wiring Harness Damage: Wires in the wiring harness running to the taillights can be damaged by age, rubbing against metal parts, or rodent damage. A frayed wire touching ground will cause a short. You'll need to carefully inspect the harness, particularly where it enters the body and around the taillights.
* Shorted Bulb: While less common than a bad socket, a shorted bulb filament can also blow the fuse. Try replacing the bulbs, even if they appear to be working.
* Bad Ground: A poor ground connection can cause excessive current draw, blowing the fuse. Check the ground connection points for the taillights; these are usually near the taillights themselves. Clean any corrosion.
* Water Intrusion: Water getting into the taillight assemblies can cause corrosion and shorts. Check for any signs of water leaks around the taillights.
* Aftermarket Modifications: If you've added any aftermarket lights or wiring, they could be the source of the problem. Check any additional wiring for shorts or improper connections.
Troubleshooting Steps:
1. Check the Fuse: Make sure you're replacing the fuse with the correct amperage. Using a higher amperage fuse is dangerous.
2. Visual Inspection: Thoroughly inspect the wiring, bulbs, and sockets. Look for any signs of damage, corrosion, or water intrusion.
3. Test the Bulbs and Sockets: With the bulbs removed, test the sockets for continuity to ground. If you find a short to ground, replace the socket.
4. Check the Wiring Harness: If you suspect harness damage, carefully trace the wires from the fuse to the taillights, looking for any breaks or frayed wires.
If you're uncomfortable working with car electrical systems, it's best to take your S-10 to a qualified mechanic. Improperly working with car electrical systems can be dangerous.
