Sunroof

SUNROOF

DESCRIPTION

General
Operation of the sunroof is controlled via the three position switch located on the front of the headlining. Moving the switch rearwards opens the sunroof. Similarly, moving the switch forward closes the sunroof. A single press in the center of the switch opens or closes the sunroof from the tilt position.

All switch inputs are registered by the sunroof ECU, which is located behind the front of the headlining, adjacent the sunroof motor. The sunroof ECU also receives messages from the Body Control Unit (BCU) via the P-Bus to enable it to carry out its automatic closing and opening routine. Automatic closing is carried out when the 'Land Rover' button on the remote handset is pressed and held for longer than 2 seconds. Similarly, pressing and holding the 'Arrow' key on the remote handset for longer than 2 seconds opens both the sunroof and all windows.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 53, and fuse 58 of the passenger compartment fuse box (C0632) on an R wire. Fuse 58 (C0582) provides a constant battery feed to the sunroof ECU (C0784) on an RS wire. Fuse 53 (C0583) provides a constant battery feed tn the ignition switch (C0028 on V8 vehicles) on an R wire. When the ignition switch is turned to the 'auxiliary' position, current flows across the switch (C0028 on V8 vehicles) to fuse 41 of the passenger compartment fuse box (C0585) on a PB wire. Fuse 41 (C0586) provides an auxiliary ignition feed to the Body Control Unit (BCU) (C0660) on a PW wire.

Sunroof ECU
The sunroof ECU (C0784) provides afeed to the sunroof switch (C0363) on a YS wire. If the switch is moved to the 'Open' position, a feed is returned to the ECU (C0784) on a YG wire. The ECU will now power the sunroof motor to open the sunroof. By measuring the voltage pulses returned from two Hall effect sensors located within the sunroof mechanism, the ECU can determine when the sunroof has reached the end of its travel and cut the voltage supply to the motor.

If the switch is moved to the 'Close' position, a feed is returned to the sunroof ECU (C0784) on an SB wire. The ECU will now power the sunroof motor to close the sunroof. By measuring the voltage pulses returned from the two Hall effect sensors, the ECU determines when the sunroof has reached the end of its travel and cuts the voltage supply to the motor.

If the center of the switch is pressed, a feed is returned to the sunroof ECU (C0784) on a YW wire. The ECU will now power the sunroof motor in the 'Close' direction to raise the rear of the sunroof. By measuring the voltage pulses returned from the two Hall effect sensors, the ECU determines when the sunroof has reached the end of its travel and cuts the voltage supply to the motor.

If the center of the switch is pressed a second time, a feed is returned to the sunroof ECU (C0784) on a YW wire. The ECU will now power the sunroof motor in the 'Open' direction to lower the sunroof. By measuring the voltage pulses returned from the two Hall effect sensors, the ECU determines when the sunroof has reached the end of its travel and cuts the voltage supply to the motor.

The sunroof ECU (C0784) is earthed on an N wire.

Body Control Unit (BCU)
The Body Control Unit (BCU) (C0660) communicates with the sunroof ECU (C0784) via the P-Bus. In addition to enabling automatic opening and closing to be carried out, the BCU also triggers the sunroof ECU into an energy saving 'sleep' mode.