1. Check the Window Switches:
* Passenger Window Switch: The most likely culprit. These switches are notorious for failing. Try spraying some electronic contact cleaner (like DeoxIT) into the switch while working it up and down repeatedly. This might dislodge debris or corrosion. If the cleaner doesn't work, the switch likely needs replacement.
* Master Switch (Driver's Side): Even though the driver's window works, a faulty master switch can still prevent the other windows from functioning correctly. It's possible the circuits controlling the passenger and rear windows are damaged within the master switch. Again, contact cleaner might help, but replacement is more likely necessary.
2. Check the Wiring:
* Visual Inspection: Inspect the wiring harnesses running from the switches to the window motors. Look for any obvious signs of damage (cuts, fraying, corrosion). Pay close attention to the areas where the wires bend and flex.
* Continuity Test (Advanced): If you have a multimeter, you can test the continuity of the wires. This requires disconnecting the wires from the switches and motors and checking for a continuous path. This is more advanced and requires some electrical knowledge.
3. Check the Window Motors and Regulators:
* Accessibility: Accessing the window motors and regulators usually involves removing the door panels. This is a moderately difficult task, requiring patience and some basic tools. Search online for a repair manual or video specific to your 1998 Infiniti I30 for detailed instructions.
* Testing: Once you have access, you can test the motors directly using 12V power (with caution!). If the motor doesn't work, it needs replacing. A faulty regulator (the mechanism that moves the window) is also a possibility. These are usually replaced as a unit with the motor.
4. Power Window Relay (Less Likely but Possible):
Some vehicles use a relay to control the power windows. While less likely in your case since the driver's window works, a faulty relay *could* be preventing power from reaching the other windows. Consult a wiring diagram to locate this relay (if it exists) and test its functionality.
5. Ground Connection Issues:
A poor ground connection can disrupt the electrical flow to the windows. Check the ground points associated with the window system within the car's wiring harness. These are often located near the door panels. Clean any corrosion from the ground connections.
Important Notes:
* Safety First: Disconnect the negative battery terminal before working on any electrical components in your car.
* Repair Manual: A repair manual specific to your 1998 Infiniti I30 is highly recommended. It will provide detailed diagrams, instructions, and torque specifications.
* Professional Help: If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. Incorrect repairs can lead to further damage.
Start with the simplest and least invasive steps (switches and visual inspection) before moving to more complex ones (motor/regulator replacement). Document your findings as you go to help diagnose the problem efficiently.
