Windows: Description and Operation
WINDOWS
DESCRIPTION
General
Operation of all four windows is controlled by the Body Control Unit (BCU) via the P-bus. The P-bus allows communication between the BCU and the drivers and passenger door modules. The door modules are mounted in the relevant front door. The drivers door module features four rocker switches, and a non-latching switch to inhibit operation of the rear windows. A rocker switch is also located on the front passenger door, and both rear passenger doors for operation of the relevant window.
Both front and rear windows feature an anti-trap function. If an obstacle is detected while the window is being closed, it will return to the fully open position.
OPERATION
Front
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 11, fuse 24, and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 11 (C0585) provides a constant battery feed to the drivers door module (C2017) on an RP wire. Fuse 24 (C0583) provides a constant battery feed to the passenger door module (C2016) on an RW wire.
Fuse 53 (C0583) provides a constant battery feed to 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. The BCU (C0662) is earthed on an N wire.
Drivers Window
When the drivers door switch is moved to the Up position, the feed from fuse 11 of the passenger compartment fuse box (C0585) flows through the drivers door module (C2017) to earth on an N wire. The drivers door module (C2017) will now provide a feed to the window lift motor ( 20740) on a BS wire. Current flows across the motor and back to the drivers door module (C2017) on a BG wire. The drivers door module provides an earth path for the motor on an N wire. When the current draw of the window lift motor increases, the BCU (via the P-bus) determines the window has reached the limit of its travel and cuts the supply from the drivers door module.
When the drivers door switch is moved to the 'Down' position, the feed from fuse 11 of the front passenger compartment fuse box (C0585) flows through the drivers door module (C2017) to earth on an N wire. The drivers door module (C2017) will now provide a feed to the window lift motor (C0740) on a BG wire. Current flows across the motor and back to the drivers door module (C2017) on a BS wire. The drivers door module provides an earth path for the motor on an N wire. When the current draw of the window lift motor increases, the BCU (via the P-bus) determines the window has reached the limit of its travel and cuts the supply from the drivers door module.
Front Passenger Window
When the passenger door switch is moved to the 'Up' position, the feed from fuse 24 of the passenger compartment fuse box (C0583) flows through the passenger door module (C2016) to earth on an N wire. The passenger door module (C2016) will now provide a feed to the window lift motor (C0741) on a BS wire. Current flows across the motor and back to the passenger door module (C2016) on a BG wire. The passenger door module provides an earth path for the motor on an N wire. When the current draw of the window lift motor increases, the BCU (via the P-bus) determines the window has reached the limit of its travel and cuts the supply from the passenger door module.
When the passenger door switch is moved to the 'Down' position, the feed from fuse 24 of the front passenger compartment fuse box (C0.583) flows through the passenger door module (C2016) to earth on an N wire. The passenger door module (C2016) will now provide a feed to the window lift motor (C0741) on a BG wire. Current flows across the motor and back to the passenger door module (C2016) on a BS wire. The passenger door module provides an earth path for the motor on an N wire. When the current draw of the window lift motor increases, the BCU (via the P-bus) determines the window has reached the limit of its travel and cuts the supply from the passenger door module.
Anti-Trap
The anti-trap system consists of an anti-trap seal, which runs along the door glass frame. The seal contains two elements, with a combined resistance of 1.2 k Ohm. This resistance is constantly monitored by the BCU via the P-bus. If the window meets an obstacle, it pushes it against the anti-trap seal. This 'shorts' the two elements together, reducing the seals resistance to approximately 500 Ohm. When the BCU detects this drop in resistance, it reverses the feed to the window lift motor. Both the drivers door module (C20.58) and the passenger door module (C2057) are connected to the anti-trap seals (C0599 & C0600 respectively) by NR wires. The anti-trap seals are both earthed on N wires.
Rear
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 53 and fuse 60 of the passenger compartment fuse box (C0632) on an R wire. Fuse 60 (C0582) provides a constant battery feed to the BCU (C0662) on an RW wire.
Fuse 53 (C0583) provides a constant battery feed to 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 BCU (C0660) on a PW wire.
RH Rear Window
The BCU (C0660) provides a feed to the RH rear window switch (C0732) on SY then N and SU then SB wires. If the switch is moved to the 'Up' position, the switch contacts close momentarily, allowing the feed on the SY then N wire to flow to earth on an N wire. Sensing this earth path, the BCU (C0662) provides a feed to the RH rear window lift motor (C0304) on a BN then BG wire. Current flows across the motor (C0304) and back to the BCU (C0662) on a US then UP wire. When the current draw of the window lift motor increases, the BCU determines the window has reached the limit of its travel and cuts the supply to the motor.
If the switch is moved to the 'Down' position, the switch contacts close momentarily, allowing the feed on the SU then SB wire to flow to earth on an N wire. Sensing this earth path, the BCU (C0662) provides a feed to the RH rear window lift motor (C0304) on a UP then US wire. Current flows across the motor (C0304) and back to the BCU (C0662) on a BG then BN wire. When the current draw of the window lift motor increases, the BCU determines the window has reached the limit of its travel and cuts the supply to the motor.
LH Rear Window
The BCU (C0660) provides a feed to the LH rear window switch (C0732) on SN and SB wires. If the switch is moved to the 'Up' position, the switch contacts close momentarily, allowing the feed on the SN wire to flow to earth on an N wire. Sensing this earth path, the BCU (C0662) provides a feed to the LH rear window lift motor (C0304) on a BG wire. Current flows across the motor (C0304) and back to the BCU (C0662) on a US wire. When the current draw of the window lift motor increases, the BCU determines the window has reached the limit of its travel and cuts the supply to the motor.
If the switch is moved to the 'Down' position, the switch contacts close momentarily, allowing the feed on the SB wire to flow to earth on an N wire. Sensing this earth path, the BCU (C0662) provides afeed to the LH rear window lift motor (C0304) on a US wire. Current flows across the motor ('20304) and back to the BCU (C0662) on a BG wire. When the current draw of the window lift motor increases, the BCU determines the window has reached the limit of its travel and cuts the supply to the motor.
Anti-Trap
The anti-trap system consists of an anti-trap seal, which runs along the door glass frame. The seal contains two elements, with a combined resistance of 1.2 k. This resistance is constantly monitored by the BCU. If the window meets an obstacle, it pushes it against the anti-trap seal. This 'shorts' the two elements together, reducing the seals resistance to approximately 500 . When the BCU detects this drop in resistance, it reverses the feed to the window lift motor.
The BCU (C0661) is connected to the RH rear anti-trap seal (C2015) by an NR then NY wire, and to the LH rear anti-trap seal (C2015) by an NY wire. Both anti-trap seals (C2015) are earthed on N wires.
NOTE: Both rear anti-trap seals have the same connector number as they utilise the same harness.