Sunroof / Moonroof: Description and Operation

CIRCUIT OPERATION

The Astro Roof system consists of the glass/track assembly and three electrical components: the Astro Roof Actuator Assembly, the Astro Roof Switch, and the Astro Roof Control Module.

The glass/track assembly has three end point positions: fully closed and flush with the vehicle roof, fully open and retracted in the roof cavity, and fully vented with the rear of the glass raised to the limit of its travel.

The Astro Roof Actuator Assembly consists of a reversible DC motor, gear train, and a Limit Switch. An exposed gear transfers power to the glass/track assembly.

The Astro Roof Switch is a rocker type switch with three positions: a normal center off position, a FORWARD/VENT position, and a REVERSE/CLOSE VENT position.

The Astro Roof Control Module controls the Astro Roof Motor based on inputs from the Astro Roof Switch. Special features of the Control Module are "express open" and "express close vent," "stall sense," and "operation time-out."

The "express feature" makes it necessary to only momentarily push the Astro Roof Switch in the REVERSE/ CLOSE position to fully open the glass or to close the glass from the vent position.

"Stall sense" protects the Astro Roof by not allowing it to run for more than 0.75 seconds when the glass/track assembly is obstructed or has reached the fully open position during express open mode.

"Operation time-out" protects the Astro Roof against failure of the stall sense. The Control Module will stop any operation which is still underway 20 seconds after beginning the operation.

Power and Ground
Battery voltage is applied to the Astro Roof Control Module (terminal C1/C) through the RAP Circuit Breaker and CKT 76 whenever the ignition is in RUN or Retained Accessory Power (RAP) is energized. The voltage applied to the Control Module through CKT 76 powers the solid state circuits and the relay contacts in the Module. The Astro Roof Control Module is grounded at terminal C1/D through CKT 804. Whenever the Control Module has power applied and ground, the Module will enter the standby mode until it receives an input command from the Astro Roof Switch.

Limit Switch
The Limit Switch is a micro-switch located on the Astro Roof Actuator Assembly. The purpose of the Limit Switch is to let the Astro Roof Control Module know when the glass is in the flush closed position.

The Limit Switch is opened and closed by the large cam on the Actuator Assembly. When the Astro Roof Motor is synchronized with the glass/track assembly and the glass is in the flush closed position, the tab on the Limit Switch extends into the notch on the large cam. This closes the Limit Switch and grounds the flush input of the Control Module (terminal C2/8) through the RED and YEL wires, the Control Module, and CKT 804 to ground 0401. If the glass is opened or vented, the large cam rotates and depresses the tab on the Limit Switch which opens the switch and removes ground from the flush input of the Control Module.

Express Open/Close Vent
The Astro Roof Control Module will enter the express open or express close vent mode when the Control Module is in the standby mode and the reverse/close vent input (terminal C2/6) is momentarily grounded through the Astro Roof Switch and the BRN and WHT wires.

In response to this input the Control Module energizes the reverse coil which pulls the reverse relay contacts closed. Battery voltage (which is applied to the Control Module through CKT 76) is now applied to the Astro Roof Motor through the reverse relay contacts and the ORN wire. The Astro Roof Motor is grounded through the BLU wire, the normally closed forward relay contacts in the Control Module, and CKT 804 to ground G401. The Control Module will continue to drive the Astro Roof Motor in the open or close vent direction until:

^ Motor stall is sensed due to the glass/track assembly reaching the limit of travel in the open direction or an obstruction in the glass/track assembly.
^ The Astro Roof Switch is returned to the neutral po5ition and moved to the REVERSE/CLOSE VENT position during express operation.
^ The Astro Roof Switch is moved to the FORWARD/ VENT position during express operation.
^ The operation time-out timer in the Control Module expires, 20 seconds after the start of the express mode.
^ The flush input is grounded through the Limit Switch when in the express close vent mode.

Closing/Venting
When the Astro Roof Switch is moved and held in the FORWARD/VENT position, the forward/vent input of the Astro Roof Control Module is grounded through the Astro Roof Switch and the ORN and WHT wires.

In response to this input the Control Module energizes the forward coil which pulls the forward relay contacts closed. Battery voltage (which is applied to the Control Module through CKT 76) is now applied to the Astro Roof Motor through the forward relay contacts and the BLU wire. The Astro Roof Motor is grounded through the ORN wire, the normally closed reverse relay contacts in the Control Module, and CKT 804 to ground G401. The Control Module will continue to drive the Astro Roof Motor in the close or vent open direction until:

^ The Astro Roof Switch is returned to the neutral position.
^ The flush input is grounded through the Limit Switch indicating that the glass is in the flushed closed position.
^ The operation time-out timer in the Control Module expires, 20 seconds after the start of the forward/ vent command.