GM Service Manual Online
For 1990-2009 cars only

Power Retractable/Moveable Top System Components

The power retractable/moveable top system consists of the following components:

    • Roof door module (RDM)
    • Hydraulic system including pump motor
    • Hydraulic lines and valve manifold
    • Electronic actuator for latching the top to the header
    • Folding top mechanics for the top:
       - Top
       - Stowage compartment lid panel
       - Stowage compartment lid extension panel
       - Latching mechanism for the top
    • Serial data communication
    • Position sensing hardware:
       - Limit switches
       - Hall effects as position sensors of the cylinders
    • Top open/close control switch
    • Power supply:
       - RDM/windows 30 circuit breaker
       - PWR roof 30A circuit breaker
       - RDM2 15A fuse
       - IGN 0 10A fuse
    • Grounds:
      • G300
      • G301

System Operation

Before any movement of the top is allowed, the following messages must be received by the RDM and may also be retransmitted periodically:

    • Ignition in ACCY, RUN or RAP
    • Brake is pedal pressed
    • Vehicle speed less than 5 mph
    • A/C is OFF
    • Cargo cover is closed

The sequence for opening the top is as follows when holding the retractable roof switch to the OPEN request position:

  1. Driver and passenger windows index down
  2. Tonneau latch extending to unlatch
  3. Tonneau latch extended, opened
  4. Tonneau panel extending upward, opening
  5. Tonneau panel extended upward
  6. Front tonneau extending
  7. Front tonneau extended
  8. Header latch unlatching
  9. Top panel dowel pins activate that top panel is not over center and unlatched
  10. Top panel retracting, to open position
  11. Top panel retracted to open position
  12. Tonneau panel retracting downward, closing
  13. Tonneau panel closed
  14. Tonneau latch, retracted
  15. Audible chime 2 times indicated cycle completed

The sequence for closing the top is as follows when holding the top retractable roof switch to the CLOSE request position:

  1. Driver and passenger windows index down
  2. Tonneau latch extending to unlatch
  3. Tonneau latch extended, opened
  4. Tonneau panel extending upward, opening
  5. Tonneau panel extended upward
  6. Top panel extending to close position
  7. Top panel dowel pins enter receiver indicating top reached header
  8. Header latch latching
  9. Top panel dowel pins activate that top panel is over center, latched
  10. Front tonneau retracting
  11. Front tonneau retracted
  12. Tonneau panel retracting downward, closing
  13. Tonneau panel closed
  14. Tonneau latch, retracted
  15. Audible chime 2 times indicated cycle completed
  16. Driver and passenger window close

Hydraulic Control

The roof door module (RDM) will control the hydraulic system to move the folding top by controlling the on/off state and direction of the hydraulic pump motor, and the open/close state of each valve.

The pump motor will be continuously monitoring the temperature sensor thermistor for a pump motor temperature being out of range. If the RDM detects a temperature between the pump motor pre-alarm and pump motor alarm, the current open/close operation shall complete, but no new top operation will be allowed until the pump motor cools below the pump motor pre-alarm. If the temperature reaches the pump motor alarm value, all top operation will cease. There is a low temperature value that will also cease all operation when the temperature is below this value.

Anytime the folding top control switch is released or the top becomes inoperative when it is not fully closed or open, pressure must be maintained in the system to avoid drifting and damage of components. After 4 minutes, hydraulic pressure should be released by cycling the valves on and off, allowing the top to gradually settle to a resting position.

Driver Notification

Listed below are under certain conditions the driver shall be alerted with a message sent via class 2 serial data to the driver information center (DIC).

    • ROOF CYCLE TIMEOUT -- Displays when the folding top switch is active and the RDM has detected a fault that could potentially bind the system possibly causing mechanical damage. Roof operation ceases when this message appears.
    • PUT VEHICLE IN PARK -- Displays when cargo cover is released as vehicle is out of park.
    • STOP VEHICLE -- Displays when cargo cover is released as vehicle is moving.
    • ROOF AJAR -- Displayed when cargo cover is released and roof system is not fully opened or closed.
    • CARGO COVER AJAR -- Displays when folding top switch is active and the cargo cover is open or ajar.
    • PRESS BRAKE -- Displays when folding top switch is active while vehicle is stopped and the brake is not pressed.
    • REDUCE SPEED -- Displays when folding top switch is active while vehicle is above a maximum speed.
    • UNKNOWN ROOF POSITION -- Displays when folding top control switch is active as either the folding top panel, stowage compartment lid panel or stowage compartment lid extension panel exceed the parameters of there set positions.
    • HDR LATCH SWITCH FAULT -- Displays when folding top control switch is active and a fault is present with either the latched or unlatched limit switch.
    • ROOF HALL SWITCH FAULT -- Displays when folding top control switch is active and a fault is present with either the top panel extended or retracted hall effect switch.
    • TONN HALL SWITCH FAULT -- Displays when folding top control switch is active and a fault is present with the stowage compartment lid panel extended hall effect switch.
    • TLAT HALL SWITCH FAULT -- Displays when folding top switch is active and a fault is present with the stowage compartment lid panel latched, left or right, hall effect switch.
    • TONN LATD SWITCH FAULT -- Displays when folding top switch is active and a fault is present with either the left or right, stowage compartment lid panel latched switch.
    • FLIP HALL SWITCH FAULT -- Displays when folding top switch is active and a fault is present with either the stowage compartment lid extension panel retracted or extended hall effect switch.

Switches

The folding top system monitors inputs from hall effect switches to determine the position of various components and to control the folding top system sequence. A hall effect switch that is attached to a hydraulic cylinder will become active, 1.5-3.5 volts output to RDM, as a cylinder reaches it's fully extended or retracted position based on the location of the hall effect switch.

The stowage compartment lid extension panel hall effect switches become active as the stowage compartment lid extension panel cycle approaches the extended or retracted positions. The hall effect switches are active as they sense the magnetic field as the cylinder approaches each end of it's travel, causing the switch to become active, 1.5-3.5 volts.

The operating sequences between the folding top roof panel and the windshield header are monitored by the RDM from a combination of switches:

    • The header has a folding top outer latch actuator with 2 limit switches that monitor the header latch position. These 2 inputs are combined as the Header Latch Switch parameter.
    • The LH pin guide receiver has a limit switch to monitor the roof panel dowel pin position to the header. This is monitored as 2 parameters, the Roof Dowel Pin Switch and the Header Over-Center Latch Switch.

As the folding top panel is closing up to the header, the dowel pin, as it first enters the pin guide receiver, signals the RDM that the top is at the header and aligned, as the Roof Dowel Pin Switch status is Engaged. The RDM will control the folding top outer latch actuator to latch, pulling the top panel closer into the header. The dowel pin will enter further into the pin guide receiver, again signaling that the top is now over-center and latched as the Header Over-Center Latch Switch status becomes Active. The folding top outer latch position switch will also signal an input to the RDM confirming that the top is latched and to stop the control outputs to the folding top outer latch actuator. The Header Latch Switch status would update from Released to Transition to Latched.

Class 2 Communications

The RDM communicates via class 2 to determine the status of the vehicle out of park, and vehicle speed. These parameters are monitored and can inhibit top operation.