Operation CHARM: Car repair manuals for everyone.

Principles of Operation (How Does It Work?)

Roof Opening Panel Control Module
Battery power is continuously supplied to the roof opening panel control module. However, the roof opening panel will only operate from the roof opening panel switch with the ignition switch in the RUN or ACCY position. The global open and close feature is controlled by two circuits from the rear electronic module (REM). The two circuits must be at ground potential before the roof opening panel control module will acknowledge the roof opening panel switch. When the ignition switch is turned to RUN or ACCY, the REM provides ground to these circuits.

The roof opening panel control module incorporates soft stops at the end of all travel positions. The roof opening panel control module monitors the internal switches to determine the roof opening glass position and the soft stops. The internal switches are activated by the roof opening panel motor rotation.

The roof opening panel control module supplies the power and ground to the roof opening panel motor depending on the ordered function. Power is supplied to the roof opening panel motor for a maximum of 12 seconds. Under normal operation, position is monitored by the roof opening panel control module and power is removed from the roof opening panel motor as soon as the roof opening panel reaches the commanded position.

Roof Opening Panel Switch
Four circuits connect the roof opening panel switch to the roof opening panel control module. One circuit is the common return. The other three are the control circuits open, close and tilt. The roof opening panel control module monitors these lines for voltage fluctuation to determine which function was selected.

With the ignition switch in the RUN or ACCY position, the roof opening panel supplies a five volt reference voltage to the three control lines. Activation of the roof opening panel switch connects one or more of these lines to the common return which pulls the line low. The roof opening panel control module will sense the line or lines being connected to the common line and carry out the appropriate function.

The express open function connects the open and tilt circuits to the common return when the roof opening panel switch is moved rearward to the second detent position. The operator-controlled open function connects the open circuit to the common return. The close function connects the close circuit to the common causing the roof opening panel to close from a slide or vent position.

Global Open and Close
Two circuits connect the REM to the roof opening panel control module for these functions. Global open and close operation for the roof opening panel is controlled by one of these two circuits being grounded by the REM.

Global open and close operation is only available with the ignition in the OFF position and the ignition key removed.

When the ignition switch is in the RUN or ACCY position, the REM grounds both of these circuits allowing normal operation of the roof opening panel from the roof opening panel switch.

When global open or close operation is selected, the roof opening panel switch is not recognized by the roof opening panel control module throughout the operation and five seconds after the operation is completed.

With the ignition switch in the OFF position, the roof opening panel control module supplies a constant voltage to these two circuits. The roof opening panel control module monitors these lines for a low state, caused by the REM grounding the line, to determine the ordered global function by the REM.

Global open is commanded by the REM grounding control line two. Line one will remain at previous voltage.

Global close is commanded by the REM grounding control line one. Line two will remain at previous voltage.

If both lines have voltage, the roof opening panel will be inoperative.

The global open function is activated by:
^ unlocking the driver door using the remote keyless entry transmitter. Within five seconds, press and hold the unlock button.
^ unlocking the driver door using the driver door lock cylinder and the key. Hold the key in the unlock position.

The global close function is activated by:
^ turning the driver door lock cylinder to the lock position and holding.

Global open and close operates as follows:
^ With the roof opening glass in the flush position, activating global open will operate the roof opening glass to the full open position.
^ With the roof opening glass in the open position, activating global close will close the roof opening glass to the flush position.
^ If a global open is commanded within five seconds of a completed global operation, the roof opening panel control module will reverse the previous completed global operation. If the roof opening glass was globally closed from the vent position, a global open within five seconds would tilt the roof opening glass back up.
^ If the roof opening glass was globally closed from the slide open position, a global open within five seconds would slide the roof opening glass back open.