Principles of Operation (How Does It Work?)

Front Electronics Module (FEM) and Rear Electronics Module (REM)
The driver power window is controlled by the FEM. The passenger power window is controlled by the REM. The master window control switch can control the driver and the passenger windows. The master window control switch is hardwired to the FEM. When the passenger window is activated on the master window control switch, the signal is sent to the passenger control switch from the master switch. This signal does not go through the FEM module. The door ajar switches are hardwired to the FEM. The FEM communicates through the SCP network to the REM for passenger door ajar signal.

Driver Window
The power driver window feature provides the operator with local, proportional control over the driver window. During proportional control, a request will be generated for window motion as long as the master control window switch remains pressed. This window has the one-touch down feature.

Passenger Window
The passenger power window feature provides the operator with local, proportional control over the passenger window. During proportional control, a request will be generated for window motion as long as the master window control switch or passenger window control switch remains pressed.

Short Drop Driver and Passenger Windows
The short drop driver and passenger window feature determines when to carry out a driver or passenger window short drop command, in order to drop or close a single window or both windows when a door is ajar or the convertible top switch is activated. When the driver or passenger door is ajar, the appropriate window will drop. After the open door is closed, the window will then close. If the convertible top switch is activated, causing the windows to drop, both windows will close if the PRNDL is taken out of PARK or if one door becomes closed.

If the FEM/REM have been entered into the diagnostic mode while the windows are dropped, the windows will need to be manually raised by using the window control switches. Calibration of the short drop feature will not be affected.

One-Touch Down
The one-touch down feature provides the operator with local, one-touch down control over the driver window. The window will be requested to move down to the fully open position after a single, momentary press of the master window control switch.

Heated Backlight
The heated backlight eliminates condensation on the rear window. The REM activates an external relay to power the grid on either the convertible top or removable hardtop. The command from the DATC heated backlight switch is sent through the SCP network link to the REM. The REM will then activate the heated backlight relays. The heated backlight will not function with the convertible top in the down position.

Delayed Accessory
The delayed accessory feature allows the power windows to function after the ignition is turned off until any door is opened. Then the REM receives the status from the FEM that the driver or passenger door is ajar, the REM will turn off the power to the master and passenger window control switches.

Diagnosis
The FEM and REM constantly monitor systems under their control and report a concern in the form of a Diagnostic Trouble Code (DTC). DTCs can be retrieved with the diagnostic tool or an equivalent tester through the SCP communication network.

This vehicle's design makes it unique in that electronic functions are divided into zones. These systems rely heavily on the SCP communication network in order to transmit and receive messages. It is vital when diagnosing this vehicle's electronic systems, to understand:
^ where the input (command) originates.
^ all input information messages necessary in order for a feature to operate correctly.
^ which module(s) receive(s) the input (or command message).
^ if the module which received the input (message) controls the output of the feature, or does it output a message over the communication network to another module.
^ which module controls the output of the feature.

Delayed Accessory
Delayed accessory operation allows the power windows and the radio to operate for up to 10 minutes after the ignition is turned to OFF. The delayed accessory function is controlled by the REM. When the ignition switch is turned from RUN to OFF, the REM will begin the timing sequence. if a door is opened or the ignition switch is activated to another position, the REM will cancel the delayed accessory operation.