1. Check the Fuse:
* Locate the fuse box: Your Expedition likely has two fuse boxes – one under the hood and one inside the passenger compartment (often under the dash). Consult your owner's manual to identify the correct fuse for the passenger power window.
* Inspect the fuse: Look for a blown fuse (it will be visibly broken or discolored). Replace it with a fuse of the same amperage if necessary. If the fuse blows immediately after replacement, there's a short circuit somewhere in the system – proceed cautiously.
2. Check the Window Switch:
* Test the switch: Try operating the window switch in different positions (up, down). If the switch feels unresponsive or makes clicking sounds, it might be faulty. Try the switch in all positions several times as sometimes this is enough to restore function.
* Test with a different switch: If your Expedition has power windows in the driver's side door, try using the driver's switch to operate the passenger window. If it works, the problem lies with the passenger-side switch.
* Test the switch with a multimeter: If you have a multimeter, you can test the switch's continuity to confirm it's working correctly. This requires some electrical knowledge.
3. Check the Window Motor:
* Access the motor: This usually requires removing the door panel. There are plenty of videos online showing how to do this for a 1999 Ford Expedition. Be careful not to damage any clips or wires.
* Test the motor: Once you have access, you can try to directly power the motor (using the correct voltage and polarity – this is also where a multimeter is very handy, but if done incorrectly can cause injury) to see if it works. If it does, the problem is likely with the switch or wiring. If it doesn't, the motor is likely faulty.
4. Check the Window Regulator:
* Inspect the regulator: The regulator is the mechanism that moves the window up and down. While you have the door panel off, inspect the regulator for any broken or bent parts. This is often the weak point in window systems, and they can be quite pricey to replace.
5. Check the Wiring:
* Inspect the wiring: Look for any broken, frayed, or corroded wires between the switch, the motor, and the regulator. Pay close attention to the area where the wires enter and exit the door. This is a common point of failure due to repeated flexing.
* Use a multimeter: A multimeter can help determine if there's continuity in the wiring harness.
6. Consider Professional Help:
If you're not comfortable performing electrical work or disassembling car parts, take your Expedition to a qualified mechanic. They have the tools and experience to diagnose and fix the problem efficiently.
Important Notes:
* Disconnect the battery negative terminal before starting any electrical work to prevent shorts and potential injury.
* Consult a repair manual: A repair manual specific to your 1999 Ford Expedition will provide detailed instructions and diagrams for accessing and repairing the power window system.
* Watch online videos: YouTube has many videos demonstrating how to repair power windows in similar vehicles. These can be extremely helpful in visualizing the process.
By systematically checking these components, you should be able to isolate the cause of your malfunctioning passenger power window and hopefully fix it without too much trouble. Remember safety first!
