NOTE: Power window master switch is located on driver's side front door and power window switches are located on all other passenger doors. For testing of power window switch, see POWER WINDOW SWITCH . Power window master switch may also be referred to as the driver's door Electronic Control Unit (ECU). The only testing available from manufacture for power window master switch is one touch power window system which consists of the auto up or down feature.

Power window master switch is located on driver's side front door. See Figure. Current draw should be checked. If using ammeter with measuring probe to check current draw, go to next step. If using ammeter without measuring probe, go to step 4.
Remove power window master switch and then reinstall electrical connector on power window master switch. Connect probe for ammeter at terminal No. 5 at electrical connector for power window master switch. See Fig 1.
Turn ignition on and place the auto switch for driver's side power window in the down position. Note current draw while the window goes down and when window is fully downward. The Positive Temperature Coefficient (PTC) will open within 4-90 seconds after the window stops going downward so current draw with window fully downward must be checked before the PTC opens. Current draw as window goes down should be approximately 7 amps and current draw with window fully downward should increase to approximately 14.5 amps or more. If current draw is as specified, replace power window master switch.
Disconnect electrical connector at power window master switch. Connect ammeter and battery between specified terminals on electrical connector for power window master switch. See Fig 1. Note current draw while the window goes down and when window is fully downward. The Positive Temperature Coefficient (PTC) will open within 4-90 seconds after the window stops going downward so current draw with window fully downward must be checked before the PTC opens. Current draw as window goes down should be approximately 7 amps and current draw with window fully downward should increase to approximately 14.5 amps or more. If current draw is as specified, replace power window master switch.

Fig 1: Connecting Ammeter At Power Window Master Switch
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Power Window Master Switch

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?