The power window switches for the passenger door and both rear doors stopped working. All 3 switches were replaced, but they only work sporadically. Now I'm told that the master switch on the driver's door is causing the problem, even though it continues to control the other 3 windows, and needs to be replaced. I questioned the replacement of the original 3 swithces and was told that they should be replaced whenever the master switch is replaced. Is this true?

You say the driver window works? wouldn't be a main fuse or fusible link then -driver door locks and window wouldn't work either. Each door has a module inside (computer) . The driver door has a circuit breaker power feed an a fuse DDM fuse 10amp located in rear junction block circuit breaker is located in under hood maxi fuse block. The circuit breaker also feeds battery voltage to the other door modules too. PDM - passenger door module fuse 10amp located in the instrument panel fuse box and the RDM - rear door module RDM fuse 10amp located in the rear fuse box - under the back seat.

Each power window is connected to a permanent magnet motor. The motor raises or lowers the glass when the door module applies voltage to the motor. The direction the motor turns depends on the polarity of the supply voltage provided by the associated door module. The 2 front doors have their own separate modules. The rear seat contains a single module, which controls both of the rear power windows.
A serial digital communications link, called the simple bus interface, is used for communications between door modules and the driver's door power window switches. The use of serial digital communications allows the use of a single wire to convey switching information between the power door lock switch and the driver's door module (DDM). The serial communication is also used in order to transmit switching information from the DDM to the other 2 door modules.
The door modules apply battery voltage of the correct polarity to the respective window motor when any local, or power door lock switch, UP switch is operated, driving the window up. Battery voltage is applied to the respective window motor in the opposite polarity when any local, or power window switch, DOWN switch is operated, driving the window down.

Driver Door Module (DDM)
The driver's door module (DDM) directly controls the driver's door window motor and the express down window feature. The DDM sends window UP/DOWN messages received from the power door lock switch to the passenger door module (PDM) and to the rear door module (RDM) over the simple bus interface (SBI) line. The DDM also contains a class 2 data link which communicates with the other vehicle system modules. The left front power door locks and the outside power mirror are also controlled through the DDM.
Passenger Door Module (PDM)
The passenger door module (PDM) controls the passenger's door window motor. The PDM controls the passenger's door window directly from the right front power window switch or from instructions over the simple bus interface (SBI). The right front power door locks and the outside power mirror are also controlled through this module.
Rear Door Module (RDM)
The rear door module (RDM) controls both of the rear door window motors. The RDM controls the rear windows directly from the rear door window switches or from instructions over the simple bus interface (SBI).

After I verify both driver window control switch and the passenger wdo control switches don't cause the window to operate, I turn off engine and go on ACC Mode and listen for a relay clicking in the door or the BCM while you operate the switch. If you hear a click, then it's a bad wdo motor.

Replace the master switch assembly.

BCM is bad or has no power.

Yes they run a wire loom that has wires that are not used in some models. One thing you need to check is the wire loom because it flexes every time the door opens and closes and wires can break .Also you may want to go to autozone website and make a free account, you can put in the year make and model and look for the free repair guides for wire diagrams.

Motor burned out

Rather then swaping parts that don't fix it , testing the electrical is the proper way to diagnose . Using a wiring diagram to locate testing point's in the circuit . Tesing for B+ voltage at the switch , in an out , at the motor etc.... How to test power window switch motor 1985 2001 Toyota

How To Diagnose your Power Window Problem Is the Switch or motor bad

The Trainer 24 Power Window Troubleshooting

Look at the body control module.

you most likely have a power/ground/switch issue in the drivers door. the power for the other three doors must first travel through the switches in the driver door before it goes to the passengers. hence the reason why when somebody rolls down a passenger window and you push the up button on the driver door the window stops moving. the wires can break inside the rubber boot in the door jam. you can also have an internal problem with the driver door switch unit. you would need a wiring diagram to diagnose this concern.

Does the rear window work from the passenger switch?