* Wiring Harness: The most likely problem is a broken or corroded wire in the wiring harness running from the switch to the motor. Check the harness for damage, especially near the door jamb where the wires flex as the door opens and closes. Look for breaks, chafing, or corrosion. A multimeter can help identify a break in the circuit.
* Window Regulator: The window regulator is the mechanism that moves the window up and down. If it's broken or jammed, the motor won't be able to move the window even if it's working. You might need to remove the door panel to inspect this. Common regulator problems include broken cables or a stripped gear.
* Bad Ground: A poor ground connection can prevent the motor from receiving the necessary power to operate. Check the ground wire connected to the motor and the chassis for corrosion or looseness. Clean any connections you find to be dirty or corroded.
* Fuse or Circuit Breaker: Although less likely since you've already replaced the motor, a blown fuse or tripped circuit breaker could still be preventing power from reaching the motor. Check your car's fuse box and any relevant circuit breakers.
* Incorrect Motor Installation: Double-check that you installed the new window motor correctly. Even a small misalignment can prevent it from working. Refer to a repair manual or online resources for proper installation procedures.
* Door Lock/Window Switch Interlock: Some vehicles have a system that prevents window operation if the door is unlocked or certain other conditions exist. Ensure this isn't interfering with your window operation.
Troubleshooting Steps:
1. Visually inspect the wiring harness: This is the easiest and often the most fruitful step.
2. Check fuses and circuit breakers: A simple but often overlooked step.
3. Test the power at the motor: Use a multimeter to check if power is reaching the motor's connector when the switch is activated. This will help pinpoint if the problem is before or after the motor.
4. Remove the door panel: This allows you to thoroughly inspect the window regulator and wiring harness.
5. Check the ground connection: Clean or replace the ground wire if necessary.
If you're not comfortable working on car electrical systems, it's best to take your Sunbird to a qualified mechanic for diagnosis and repair. Trying to troubleshoot electrical issues without the right tools and knowledge can lead to further damage.
