Description

Component Descriptions

Hydraulic Pump

Located in the right side of the luggage compartment. The pump can be operated in two directions depending on the required direction of the convertible top (push direction - pistons extend, pull direction - pistons retract). There is a separate fluid outlet for each direction since the fluid returns through the other outlet which then functions as an inlet.

Convertible Top Hydraulic Cylinders

Located on each side of the rear seat, they are attached between the body and the convertible top frame. When hydraulic fluid is pumped into the base of the cylinders the pistons extend, raising the convertible top. Fluid directed to the top of the cylinders cause the pistons to retract, lowering the convertible top.

Latch Mechanism Hydraulic Cylinder

Located above the windshield in the latch plate assembly, the cylinder controls the convertible top latching mechanism which basically comprises a claw and two locking pins. The cylinder, either locks or releases the latching mechanism. At the end of the convertible top closing cycle, the claw engages the convertible top and pulls it into the latch position, where the locking pins secure the convertible top in place. On receiving a request for the convertible top to be opened, the cylinder retracts the two locking pins and opens the claw, releasing the convertible top, allowing the convertible top cylinders to take over the convertible top opening cycle.

Hydraulic Pump Control Relays

The relays are located in the luggage compartment fuse box.

When the Top Up Relay is energized, the hydraulic pump is in convertible top raising mode (push direction - pistons extend).

When the Top Down Relay is energized, the hydraulic pump is in convertible top lowering mode (pull direction - pistons retract).

The two relays are controlled directly by the Security and Locking Module (SLCM) located below the fuse box in the luggage compartment.

Hydraulic Control Solenoid Valves (Latch Control Valve and Main Control Valve)

Located on top of the convertible top's hydraulic pump, the solenoids are identified by colored dots: Latch Control Valve = Blue, Main Control Valve = Orange.

Both solenoids are controlled by the Security and Locking Control Module (SLCM) which is located below the luggage compartment fuse box. The solenoids control the flow of fluid to and from the base of the hydraulic cylinders:

When energized, the Latch Control Valve allows fluid to be pumped into the base of the latch mechanism cylinder to extend the piston. When de-energized, the Latch Control Valve allows fluid to exit the base of the latch mechanism cylinder to allow the piston to retract.

When energized, the Main Control Valve allows fluid to be pumped into the base of the convertible top cylinders to extend the pistons. When de-energized, the Main Control Valve allows fluid to exit the base of the convertible top cylinders to allow the pistons to retract.

Convertible Top Switch

The switch is located in the center console in front of the radio.

When the switch is pressed it signals to the Body Processor Module (BPM) to either open or close the convertible top. The BPM communicates the request via the SCP - BUS to the SLCM for as long as the switch is held in the respective position.

There are five microswitches in total which inform the SLCM of the convertible top's position:

The "Top Ready To Latch" Switch, "Top Latch Closed" Switch, and "Top Closed" Switch are located in the latch mechanism, and are connected to the BPM which is located behind the glove compartment.

The "Top Down" Switch is located on the bottom of the right side convertible top cylinder and is connected to the SLCM.

The "Top Raised" Switch is located on top of the right side convertible top cylinder and is wired in series with the "Top Ready To Latch" Switch.

The BPM notifies the SLCM of any change to the "Top Ready To Latch" Switch, the "Top Latch Closed" Switch, or the "Top Closed" Switch via the vehicle SCP-BUS.

Three functions of the microswitches are given in more detail in the section Operation of Microswitches.

OPERATION OF MICROSWITCHES

Overview

"Top Ready to Latch" Switch and "Top Raised" Switch

When both of these switches are closed, the system signals that the convertible top is over center, and that the top has contacted the latch claw.

"Top Closed" Switch

When this switch is closed, the system signals that the top has been successfully grabbed by the latch claw.

"Top Latch Closed" Switch

When this switch is closed, the system signals that the latch has retracted successfully, and that the locking pins are extended.

"Top Down" Switch

When this switch is closed, the system signals that the top is completely open.

Description

When the Security and Locking Control Module (SLCM) receives a convertible top action request from the main control switch, the SLCM monitors each mechanical movement via the microswitches as the convertible top cycles through its open or close operation. The microswitches signal when the cylinders and latch mechanisms have completed each of their designated operations.

"Top Ready To Latch" Switch: Latch Claw.

^ When the claw is fully raised (open) the "Top Ready To Latch" Switch is "open circuit".

^ When the claw is in the lowered position (closed) the "Top Ready To Latch" Switch is "closed circuit".

^ On a convertible top closing cycle, the SLCM waits until the "Top Ready To Latch" Switch and the "Top Raised" Switch are "closed circuit" before it triggers the latch pins to close.

^ On a convertible top opening cycle, the SLCM is informed that the convertible top has left the claw when the "Top Ready To Latch" Switch switches to "open circuit".

Note:
The "Top Ready To Latch" Switch is wired in series with the "Top Raised" Switch therefore, both switches must be closed before the BPM input is grounded.

"Top Closed" Switch: Latch Claw.

^ The "Top Closed" Switch informs the SLCM of the position of the convertible top.

^ Before the claw lowers the convertible top into latch position, the "Top Closed" Switch is "open circuit".

^ When the claw has lowered the convertible top into latch position, the "Top Closed" Switch switches to "closed circuit".

^ On a convertible top opening cycle, the SLCM begins to power the convertible top cylinders when the "Top Closed" Switch switches to "open circuit".

^ When the "Top Closed" Switch switches to "open circuit" the hydraulic pump reverses direction to open the convertible top.

"Top Latch Closed" Switch: Latch Locking Pins.

^ When the latch claw has pulled the convertible top into latch position and the locking pins are fully engaged, the "Top Latch Closed" Switch switches to "closed circuit". In all other conditions the "Top Latch Closed" Switch is "open circuit".

^ On a convertible top closing cycle, the SLCM waits for the "Top Latch Closed" Switch to switch to "closed circuit" confirming that the convertible top is closed, before raising any glass at easy open, and sounding the chime alarm.

^ The switching of the "Top Latch Closed" Switch to "closed circuit" indicates that the convertible top opening or closing cycle has finished, therefore allowing the hydraulic pump to be switched off.

Note:
The switches in the latch mechanism are monitored. If there is a switch failure the instrument cluster will display "Convertible top Latch Fail".

"Top Down" Switch: Convertible top Hydraulic Cylinders.

^ When the convertible top cylinders are fully retracted (convertible top lowered) the "Top Down" Switch switches to "closed circuit", in all other conditions the "Top Down" Switch is "open circuit".

^ When the convertible top cylinders are fully retracted, the switching of the "Top Down" Switch to "closed circuit" retracts the latch claw.

"Top Raised" Switch: Convertible top Hydraulic Cylinders.

^ When the convertible top cylinders are fully extended (convertible top over-center in raised position) the "Top Raised" Switch is "closed circuit".

^ In all other conditions the "Top Raised" Switch is "open circuit".

^ The "Top Raised" Switch when "closed circuit" informs the SLCM that the convertible top is over center and in a safe condition for the latch claw to pull the convertible top closed.

Note:
The "Top Raised" Switch is wired in series with the "Top Ready To Latch" Switch, therefore both switches must be closed before the BPM input is grounded.

CONVERTIBLE TOP OPENING SEQUENCE

Note:
When operating the convertible top, the engine should be running to maintain maximum battery voltage.

The following is a step-by-step description of the convertible top opening sequence. It can be used for fault finding to determine at what stage the convertible top opening sequence was interrupted, therefore giving an indication of which component is malfunctioning.

Convertable Top Pump Sequence (OPENING):

The table shows the varying conditions (on = closed, off = open) of the switches, solenoids and relays as the convertible top goes through the opening cycle. The numbers in the top row of the table refer to the following description steps.

1. When the convertible top opening sequence begins the relays and solenoids will be in the off position, "Convertible top down switch" will be the only switch in the "open circuit" condition.

2. Pressing the convertible top switch will signal the Body Processor Module (BPM) to send a "Open Convertible to" signal to the Security and Locking Module (SLCM). The SLCM will open both rear quarter windows, and sound the chime alarm to warn that the convertible top is about to open.

Note:
The rear quarter windows will be powered for a maximum of 3 seconds.

3. If the front windows are closed they will be opened slightly. The SLCM will switch on relay "Top up relay" and the "latch control valve", the latch claw will start to raise.

4. As the latch raises "Convertible latch closed switch" followed by the "convertible top closed switch" will switch to "open circuit".

5. When "Convertible top closed switch" switches to "open circuit" the SLCM will switch off relay "Top up relay" and switch on relay "Top down relay". This will change the hydraulic pump from push to pull mode to start the opening of the convertible top. When the convertible top leaves the latch claw "Convertible top ready-to-latch switch" and "Convertible top raised switch" will be switched to "open circuit".

6. When the convertible top has fully opened "Convertible top down switch" will switch to "closed circuit". The SLCM will sound the chime alarm, raise any windows which it had lowered except the rear quarter windows, and switch off the "latch control valve" causing the latch mechanism to close.

7. When "Convertible top latch closed switch" is switched to "closed circuit" in response to the latch closing, the SLCM will switch off the hydraulic pump.

CONVERTIBLE TOP CLOSING SEQUENCE

Note:
When operating the convertible top, the engine should be running to maintain maximum battery voltage.

The following is a step-by-step description of the convertible top closing sequence. It can be used for fault finding to determine at what stage the convertible top closing sequence was interrupted, therefore giving an indication of which component is malfunctioning.

Convertable Top Pump Sequence (CLOSING):

The table shows the varying conditions (on = closed, off = open) of the switches, solenoids and relays as the convertible top goes through the closing cycle. The numbers in the top row of the table refer to the following description steps.

1. When the convertible top closing sequence begins the solenoids and relays will all be switched "off". The "Convertible top latch closed switch" and "Convertible top down switch" will be the only switches that are "closed circuit".

2. Pressing the convertible top switch will signal the Body Processor Module (BPM) to send a "Close Convertible top" signal to the Security and Locking Control Module (SLCM). The SLCM will sound the chime alarm to warn that the convertible top is about to close.

3. If the front windows are closed they will be opened slightly. The SLCM will turn on the "top up relay" and the "latch control valve", the latch claw will start to raise.

4. As the latch claw raises "Convertible top latch closed switch" will go "open circuit".

5. When "Convertible top latch closed switch" goes "open circuit" the SLCM switches on solenoid "main control valve"; the convertible top will start to raise.

6. When the convertible top has fully raised it will touch the latch claw which will switch "Convertible top ready-to-latch switch" to "closed circuit", and the end of the convertible top cylinder travel will switch "Convertible top raised switch" to closed circuit enabling a signal to be sent. The SLCM switches off the "Latch Control Valve"; and the claw pulls the convertible top in to the latch position allowing the locking pins to engage, securing the convertible top in place.

7. When the latch has closed "Convertible top closed switch" and "Convertible top latch closed switch" will be switched to "closed circuit", the SLCM will turn off the hydraulic pump, sound the alarm chime, and raise the front windows.

8. Further pressure on the convertible top switch will raise the rear quarter windows.