* Master Window Switch: The most common cause. The driver's side switch acts as a master control, sending power to all the other windows. If this switch is faulty, it can prevent the passenger windows from receiving power, even if the other window switches themselves are fine. A worn-out switch is a common failure point in cars of this age.
* Wiring Issues: Damaged, corroded, or loose wiring between the driver's side switch and the other window switches or motors is a very probable cause. This is especially true in older cars where the wiring harness can degrade over time. Check the wiring harness leading from the driver's switch, looking for breaks, corrosion, or loose connections. Pay close attention to the wiring loom in the door jambs, as these are often subject to flexing and wear.
* Fuse: While less likely to affect only the passenger windows, a blown fuse in the power window circuit could be the problem. Check your owner's manual for the fuse box diagram and locate the appropriate fuse for the power windows.
* Window Regulator: While unlikely to affect all passenger windows simultaneously, a faulty passenger-side window regulator (the mechanism that moves the window) might cause a malfunction, but usually would manifest as an inability to move only *that* window.
* Central Control Module (Body Control Module or BCM): In some vehicles, a faulty BCM can affect the power windows. This is less common but still a possibility. A faulty BCM would likely cause other electrical problems as well.
* Ground Issues: A poor ground connection can affect electrical systems, including power windows. Check the ground points related to the power window system.
Troubleshooting Steps:
1. Check the fuses: This is the easiest first step.
2. Test the passenger-side window switches: Try them with the ignition on, ensuring they are not internally broken.
3. Inspect the wiring: Carefully examine the wiring harness running from the driver's side switch to the passenger-side windows, checking for any obvious damage or loose connections. Pay particular attention to the area where the wiring enters and exits the doors.
4. Test the driver's side switch (if you have a spare or access to a known good one): Swapping the driver's side switch can quickly tell if that's the issue.
5. Consider professional help: If you're not comfortable working with car electronics, take your Focus to a mechanic or auto electrician. They have the tools and expertise to diagnose the problem more accurately.
The most likely culprit is a faulty driver's side master switch or damaged wiring. Start with the easiest checks (fuses and wiring inspection) before moving to more involved diagnostics.
