Scheme 1
Scheme 2
Scheme 3
RHD shown, LHD similar
The BCU controls all operations for the front windows. It controls the voltage and the earth paths to the window motors, it controls one-touch down operation and it detects stall conditions. Stall detection protects the system from sustained high current draw that occurs when a window reaches the fully up/down position or becomes stuck. When the BCU detects a stall condition, it disables operation at the stalled window until the window switch is released. Upon releasing the window switch, the BCU allows normal window operation.
The BCU receives power from fuse 34 (30A) of the passenger compartment fusebox. There is a unique earth signal between each pole of the front window switches and the BCU. This allows the BCU to determine which window motor to operate as well as which direction to operate the motor. The BCU operates the front window motors directly. There are no relays or switches between the BCU and the window motors.
The BCU disables stall detection on the front windows for a period of 500 ms when an electric window operates to allow for initial current surge to the window motor. After this period, if the BCU detects a stall signal (high current draw) for more than 300 ms, it disables the window motor until the window switch is released.
The BCU also contains the ignition switched off timeout information for both the front and the rear windows. It controls the rear window timeout function through the IDM.
TestBook communicates with the BCU and can determine the status of the front window switches. TestBook can also operate both front windows. TestBook can only determine rear window timeout status. It cannot determine the status of the rear windows, nor can it operate the rear windows.
Do not feed TestBook cables through open windows as the windows operate while performing test.
Scheme 4
The front window switches are non-latching rocker switches located in the center console. The front window switches contain illumination bulbs that operate when the side lamps or headlamps are on.
The front window switches provide earth signals to the BCU. The BCU determines which direction to operate the front window motors.
TestBook will monitor the real time status of the front window switches.
Scheme 5
The front window motors are permanent magnet motors. There is a window motor in each front door. The front window motors are controlled by the BCU.
The BCU provides both the voltage and the earth paths to the front window motors. The BCU reverses the direction the window motor operates by switching the voltage and earth paths to the window motor. The BCU also monitors stall current for the front window motors.
TestBook can operate the front window motors remotely.
Scheme 6
The rear window lift relay is a normally open relay that provides power to the rear window system. It is controlled by the IDM. The IDM receives a rear window enable signal from the BCU to allow operation during the ignition switched-off timeout period.
Both the rear window lift relay and the IDM are located in the passenger compartment fusebox. The IDM is integral to the passenger compartment fusebox.
The rear window lift relay receives voltage from fuse 13 (30A) in the passenger compartment fusebox. The IDM controls the earth side of the relay coil.
TestBook cannot monitor the status of the rear window lift relay.
Scheme 7
Scheme 8
There are two sets of switches that operate the rear windows. There is a set of rear window switches located in the center console that allow the front seat occupants to operate the rear windows. The second set of switches are located on the rear doors. All rear window switches are non-latching rocker switches.
A conventional window switch circuit controls the rear window system. In the rest position, there is battery voltage at both sides of every switch as well as at the window motors. Operating any switch provides a ground path through the switch to the window motor. Operating the switch in the opposite direction switches the voltage path and the earth path to the motor allowing the motor to run in the opposite direction.
Voltage for the rear windows is from fuse 13 (30A) in the passenger compartment fusebox through the rear window lift relay to the switches and motors.
TestBook cannot monitor the status of the rear window switches.
Scheme 9
The rear window isolation switch allows the front seat occupants to disable the rear window switches.
The rear window isolation switch is located in the center console.
The rear window isolation switch is connected in the earth path in series with the rear door window switches. Operating the rear window isolation switch interrupts the earth path to the rear door window switches, preventing the rear door switches from operating the rear window motors. The rear windows can still be operated from the center console rear window switches.
TestBook cannot monitor the status of the rear window isolation switch.
Scheme 10
There is a rear window motor located in each rear door. The rear window motors are permanent magnet motors with an integral circuit breaker that provides stall protection.
The rear window switches provide battery voltage and an earth path to the rear window motors. Operating the switch in the opposite direction reverses the voltage and earth paths at the rear window motor, allowing the motor to run in the opposing direction.
TestBook cannot monitor the rear window lift motors.
In order for the windows to operate the ignition switch must either be in position II, or in the off position with the ignition switched-off timeout operational.
The front window switches provide ground signals to the BCU, which operates the windows.
One-touch down operation
The front windows will open completely with a single touch on the window down switch.
In order for the one-touch down to operate, the following conditions must exist
- Ignition switch in position II, or in the off position with the ignition switched-off time out operational.
- Front window switch pressed for less than 0.4 second.
When the front window down switch is pressed for less than 0.4 second, the window opens completely. Pressing the window up switch for less than 0.2 second stops the movement of the window. The BCU stops one-touch down operation when it detects window stall current or after 10 seconds of window operation.
Depending on market, one-touch down operation can be fitted on both front windows or on the driver's side only.
In order for the windows to operate the ignition switch must either be in position II, or in the off position with the ignition switched-off timeout operational.
The rear windows operate by the switch providing both power and ground to the window motor. Pressing one side of the switch provides a power and earth path to the window motor that allows the window motor to operate in one direction. Pressing the other side of the switch reverses the power and earth, which allows the window motor to operate in the opposite direction.
