Semi-automatic Cabriolet Convertible Soft-Top

The semi-automatic cabriolet convertible soft-top is a hydraulic system that is controlled by the soft-top module CVM III. Once the convertible top has reached the scuttle, it must be pulled down by hand using the recessed grip. The convertible top is opened fully automatically by the press of a button.

Conditions for convertible top movement

• Ignition lock in position 1 (terminal R ON)
  
• Speed < 5 km/h
  
• No hardtop fitted
  

Opening procedure

1. Operate OPEN switch
   
2. The windows are lowered
   
3. The control module signals via the K-bus to the convertible top module that the windows have been lowered.
   
4. The convertible top is unlocked at the scuttle
   
5. The convertible top is moved in the direction of the convertible top compartment
   
6. The convertible top is lowered into convertible top compartment
   
7. The locking hooks on the convertible top are closed.
   
8. The LED in the instrument cluster goes out on completion of the opening procedure.
   
9. After a waiting time of 2 seconds (with the OPEN button still pressed) the side windows are closed.
   

Closing procedure

1. Operate CLOSE switch
   
2. The windows are lowered
   
3. The control module signals via the K-bus to the convertible top module that the windows have been lowered.
   
4. The convertible top is lifted out of convertible top compartment
   
5. The convertible top is moved in the direction of the scuttle
   
6. The convertible top stops over the scuttle
   
7. The driver pulls the convertible top onto the scuttle while operating the switch in the grip recess plate. The locking hooks pull down the convertible top. The convertible top is locked at the scuttle when the LED in the instrument cluster goes out.
   
8. After a waiting time of 2 seconds (switch in grip recess plate still pressed) the side windows are closed.
   

Components

Cabriolet convertible top module (CVM III)

The cabriolet convertible top module registers the positions of the convertible top. It activates the hydraulic unit and the scuttle lock. In addition, fault codes are also stored.

Operating switch

An operating switch with two pushbuttons is provided for the purpose of opening and closing the convertible top. When pressed, the pushbuttons switch ground to the convertible top module.

LED indicator

An LED indicator is fitted in the instrument cluster which lights when the convertible top is opened and closed. The LED goes out when the convertible top is completely opened, i.e. stowed in the convertible top compartment or completely closed, i.e. locked at the scuttle. If operation of the convertible top is interrupted, the LED flashes thus indicating that the convertible top is neither of the secure end positions.

Hydraulics

The convertible top is moved by means of hydraulic cylinders. The oil pressure required for this purpose is generated by a hydraulic unit. This hydraulic unit consists of an oil reservoir that also contains the pressure pump. The pressure pump is driven by a DC motor with its current switched by two relays. The relays are fitted in the relay carrier behind the passenger's seat. The relays are activated by the convertible top module.

There are no hydraulic valves in the hydraulic unit. The polarity of the pump motor is reversed for the two directions of movement of the main pillar.

Note: Jolts in the movement of the convertible top indicate that the vehicle battery is not sufficiently charged.

Electric drive

The convertible top is locked at the scuttle by means of an electric drive. The drive is activated directly by the convertible top module. When the operator pulls down the convertible top with the grip recess plate, it is locked in position by the locking hooks entering the windscreen frame. The electric drive is activated when the Hall sensor in the grip recess plate and the Hall sensor in the windscreen frame recognize that the convertible top has been pulled down onto the windscreen frame.

The direction of rotation of the electric motor is reversed in order to unlock the convertible top.

The locking hooks are also closed when the convertible top is completely lowered in the convertible top compartment.

Hall sensors

The Hall sensors register the positions of the convertible top:

Hall sensors are current switches. The following switching limits are defined: 4mA for the OFF status and 15mA for the ON status. Ferromagnetic material must be positioned at least 1 mm in front of the sensor so that a switch can detect an object.

There are two Hall sensor circuits in the vehicle, i.e. the convertible top sensors and the body sensors.

Body sensors

• Switch, convertible top down (I01120)
  Pin assignments: 26-pin CVM connector A, pin 4 and 17
  Function: Recognizes that the convertible top is completely lowered in the convertible top compartment. The hydraulic pump is switched off and the locking hooks closed.
  
• Switch, convertible top raised (I01121)
  Pin assignments: 26-pin CVM connector A, pin 5 and 18
  Function: Recognizes that the convertible top is completely raised. The hydraulic pump is switched off. The operator must now pull the convertible top onto the windscreen frame.
  
• Switch, convertible top locked (I01119)
  Pin assignments: 26-pin CVM connector A, pin 3 and 16
  Function: Recognizes that the convertible top rests on the windscreen frame. The electric motor for locking the convertible top is activated if the switch in the grip recess plate (I01131) is operated.
  

Convertible top sensors

• Switch, scuttle locked (I01130)
  Pin assignments: 18-pin CVM connector C, pin 4 and 5
  Function: Recognizes that the hooks of the convertible top lock mechanism are completely closed. The lock drive is switched off.
  
• Switch, scuttle released (I01129)
  Pin assignments: 18-pin CVM connector C, pin 13 and 14
  Function: Recognizes that the hooks of the convertible top lock mechanism are completely opened. The lock drive is switched off.
  
• Switch, grip recess plate (I01131)
  Pin assignments: 18-pin CVM connector C, pin 6 and 15
  Function: Recognizes that the operator has pulled down the convertible top onto the windscreen frame. The electric motor for locking the convertible top is activated if the ”convertible top locked” switch is operated.
  

Hardtop switch

A sensor in the hardtop mount detects whether a hardtop is fitted on the vehicle.