1. Identify the Problem:
* Window won't go up or down at all: This could be a blown fuse, a faulty switch, a problem with the motor, a broken regulator, or a damaged wiring harness.
* Window goes down but not up (or vice versa): Likely a problem with the motor or regulator. A faulty switch is less likely in this case, as it would usually affect both up and down.
* Window moves slowly or intermittently: This often points to a worn regulator, a weak motor, or a problem with the power supply (fuse, wiring).
* Window makes unusual noises (clicking, grinding): This suggests a problem with the regulator (often the cables are binding or broken) or the motor (gears may be stripped).
2. Troubleshooting Steps:
* Check the Fuse: Consult your owner's manual to locate the fuse for the power windows. Replace it if it's blown.
* Test the Window Switch: Try the switch in different positions. If it's faulty, you'll need to replace it. This can be a relatively straightforward repair, but access to the switch varies depending on the Mustang model year.
* Check the Wiring: Inspect the wiring harness leading to the motor and regulator for any breaks, chafing, or loose connections. Pay close attention to the area where the wires enter the door. These are frequently damaged due to flexing of the door.
* Test the Motor: This requires some disassembly. You'll need to access the motor (usually in the door). You can try applying 12V directly to the motor terminals (carefully!), but be aware of the polarity. If the motor doesn't run, it's likely faulty.
* Inspect the Regulator: The regulator is responsible for moving the window glass. Common problems include broken cables, stripped gears, or worn-out parts. Accessing the regulator usually requires significant door panel disassembly. Visually inspect the cables and gears for any obvious damage.
3. Repair Options:
* Replace the Fuse: Easiest and cheapest repair.
* Replace the Switch: Relatively easy depending on your Mustang model year. You can usually buy replacement switches online or at auto parts stores.
* Repair or Replace the Motor: More challenging. Requires disassembly and potentially specialized tools. Replacing the motor is often the better option.
* Repair or Replace the Regulator: The most challenging repair. Often requires complete disassembly of the door panel and potentially specialized tools or parts. Replacing the regulator is usually recommended unless you're experienced with automotive repairs. You may be able to get a repair kit for some regulators, but a complete replacement is often simpler.
* Repair Wiring: Requires soldering skills and possibly specialized connectors if you have to splice wires.
4. Important Considerations:
* Year and Model: The specific location and access to components will vary depending on your Mustang's year and model. You'll need a repair manual specific to your vehicle.
* Safety: Disconnect the battery's negative terminal before working on the electrical system to prevent shorts or injury.
* Tools: You'll need various tools, including screwdrivers (Phillips and flathead), panel removal tools, and possibly a multimeter to test the electrical components.
Recommendation: If you're not comfortable with automotive repairs, it's best to take your Mustang to a qualified mechanic. Replacing the regulator is a complex task and can be frustrating for a novice. While replacing a switch or motor is somewhat easier, accessing these components often requires significant disassembly. A repair manual specific to your year and model of Mustang is essential for any repair attempt.
