* Wiring Issue: This is the most likely culprit. The wiring between the driver's master switch and the rear passenger window motor might be damaged, corroded, or disconnected. A break in the wire anywhere along that run will prevent the master switch from working. The door switch likely has a separate, shorter wire run to the motor, explaining why it works. Check the wiring harness carefully for any visible damage, especially near the door jambs (where wires flex frequently).
* Faulty Driver's Master Switch: The switch itself could be malfunctioning. It's possible the contact for the rear passenger window is broken or worn out, preventing power from reaching the window motor when activated from the master switch.
* Faulty Window Motor Relay (if applicable): Some vehicles use relays to control the power to the window motors. If a relay is malfunctioning or has bad connections, it might prevent the window from working from the master switch but not the individual door switch. (Less likely on a '95 Rodeo, but possible).
* Bad Ground Connection: A poor ground connection somewhere in the circuit can cause intermittent or complete failure. This would affect both the master switch and the door switch, but the symptoms might only show up with the master switch due to higher current draw on that circuit.
* Window Regulator Problems (Less Likely): While less likely, a problem within the window regulator itself *could* contribute, although it's unusual for this to only affect the master switch operation.
Troubleshooting Steps:
1. Check the fuses: Make sure all fuses related to the power windows are intact and not blown.
2. Inspect the wiring: Carefully examine the wiring harness from the driver's master switch to the rear passenger window motor. Look for any breaks, fraying, corrosion, or loose connections. Pay close attention to areas where the wires are likely to flex and bend.
3. Test the driver's master switch: If possible, test the continuity of the switch with a multimeter to see if it's sending a signal when activated for the rear passenger window. (You'll need a wiring diagram for this).
4. Test the window motor: If you can access the motor, try applying power directly to it (carefully and with the correct voltage) to see if the motor itself is working. This requires caution and knowledge of electrical systems.
5. Check grounds: Look for any loose or corroded ground connections in the power window circuit.
6. Consider a wiring diagram: A wiring diagram for your specific 1995 Isuzu Rodeo will be invaluable in tracing the circuit and identifying potential problems. These can sometimes be found online or through a repair manual.
If you're not comfortable working with car electrical systems, it's best to take your Rodeo to a qualified mechanic. Incorrect wiring can cause additional damage.
