1. Diagnosis: Identify the Problem
* No movement at all: This suggests a complete power failure, a burned-out motor, or a broken gear.
* Slow or jerky movement: This often points to worn gears, a weak motor, or binding in the mechanism.
* Movement in one direction only: Likely a problem with the motor windings or the control circuit.
* Loud grinding noise: Indicates severely worn gears or a foreign object in the mechanism.
2. Accessing the Headlight Motor
This requires removing the headlight assembly. Consult a Fiero-specific repair manual (Haynes or Chilton) for detailed instructions. This is usually a multi-step process involving removing trim pieces, potentially the bumper, and disconnecting electrical connectors. Be careful not to damage any wiring or clips.
3. Troubleshooting Steps
* Check the fuses and relays: A blown fuse or faulty relay can prevent power from reaching the motor. The owner's manual will show the fuse box layout.
* Check the power supply: With a multimeter, test the voltage at the motor connector. You should have battery voltage when the headlight switch is activated. A lack of voltage points to a problem in the wiring or switch.
* Inspect the motor wiring harness: Look for broken wires, loose connections, or corrosion. Repair or replace damaged wiring.
* Inspect the motor itself: Carefully examine the motor for any obvious damage, such as burned wires or a broken casing.
* Test the motor: With the motor disconnected from the car, try applying 12V directly to the motor terminals (observe polarity!). If it doesn't spin, the motor is likely faulty.
* Examine the gear mechanism: Once the motor is removed from the headlight assembly, check the gears for wear, cracks, or stripping. This is often the point of failure.
4. Repair Options
* Motor Replacement: If the motor is bad, finding a replacement can be challenging. Check online parts suppliers specializing in classic cars, salvage yards, or Fiero-specific forums.
* Gear Replacement: If the gears are worn, this is potentially repairable. You might need to find replacement gears (good luck!), or try carefully repairing existing gears with epoxy if the damage is minor.
* Lubrication: If the mechanism is simply binding due to lack of lubrication, try applying a small amount of high-quality grease (not oil) to the moving parts.
* Wiring Repair: Repair any broken or corroded wires using appropriate connectors and solder.
5. Reassembly:
Once you've addressed the problem, carefully reassemble the headlight assembly, paying close attention to the correct alignment and proper reconnection of all electrical connectors.
Important Considerations:
* Repair manuals: A Fiero-specific repair manual is invaluable for this task. It will provide detailed diagrams and instructions for disassembly and reassembly.
* Parts: Finding replacement parts for these older cars can be difficult. Be prepared to search extensively.
* Patience: This is not a simple repair. It requires patience, attention to detail, and potentially some mechanical aptitude.
If you're not comfortable working on car electrical systems or mechanical components, it's best to seek professional help from a mechanic experienced with classic cars. Attempting a repair without the proper knowledge and tools could lead to further damage.
