Operation CHARM: Car repair manuals for everyone.

Introduction

INTRODUCTION

The electric cabriolet top is one of a new generation of tops incorporating a series of important modifications for improved comfort and safety.

Application of a pushbutton is all that is required to open or close the top, with no manual operations whatsoever.





The chief aid in recognizing the new generation of soft-tops is the rounded lower corners of the rear window.





Other identifying features are:




New-style rain channels...

...and cloth covered seals.





OPENING/CLOSING FUNCTIONS


The control unit permits the electrically operated cabriolet top to be opened and closed with a conventional pressbutton switch.

Application of the switch in the direction for opening moves the roof from its forward, closed position to its open position at the rear. In detail, the process is as follows. The two locking motors in the roof frame rotate out of their locked position to unlock and release the mechanical connection between the windshield frame and roof frame. When this process is completed, the control unit switches over from the locking motors to the top drive motors located in the back of the vehicle. The drive motors fold the roof towards the rear by acting on a series of mechanical components. Once the rear end-position is reached, the rear limit switch (top open) is disconnected from the chassis. The control unit cuts out the drive system and the indicator lamp, which had come on with the start of the unlocking process, goes out.

Application of the pressbutton in the direction for closing activates the drive motors to return the top to the closed position. The indicator lamp lights up; the top opens out towards the front. When the roof frame comes into contact with the windshield frame, the two roof limit switches are connected to the chassis. This means that the two locking motors are in the correct position relative to the sliding block guides in the windshield frame. The control unit then switches over from the drive motors to the locking motors, which rotate to re-establish the mechanical connection between the roof frame and windshield frame. When both locking motors have reached their final locked positions, the power supply to the locking motors is cut out and the indicator lamp goes out.

The electric top can only be operated with the car radio contact active and the ignition switched off (terminal 15) and at speeds below 10 kph If the vehicle speed is greater than this, operation of the top cannot occur until the speed falls below 5 kph. The vehicle speed is determined by the evaluation of the tachometer pulse rate. If the operating button is released, the initiated process must be capable of being interrupted and reversed by selecting the opposite direction at any time. A check must be made as to whether both the control disks are in contact by not more than 0.3 seconds after the releasing activation of the locking motors. If this is not the case, the unlocking process preceding top opening should be broken off. Resumption of the opening process is only possible by renewed application of the operating pressbutton. The locking process is not involved in this check. In both the locking and unlocking processes, a check must be made to ensure that both locking motors reach their end-position before the completion of the process is indicated or activation of the top drive motor is initiated, respectively.

The two locking motors are checked individually (control disk positions), started and braked by short-circuiting. To prevent the electric motors being overloaded, maximum operating periods of 2 seconds and 30 seconds are allowed for the locking and drive motors respectively. If either of these periods is exceeded, the operating process is broken off. To resume operation, the pressbutton.must be reapplied. A telltale lamp should indicate that the top is not in either of its end-positions. The actual position of the top must be stored in the memory bank via terminal 30 after withdrawal of the ignition key and redisplayed when the ignition lock is returned to its radio contact position. If terminal 15 is activated, the telltale lamp should light up for approximately 5 seconds for checking purposes. If, when the roof is being closed, the locking motors are prevented by a mechanical fault from assuming the correct position relative to the windshield frame, a limit switch interrupts the closing operation before the rear gear elements reach their dead center.


CONTROL CHARACTERISTICS

If the operating process is interrupted with the locking motors in the unlocked position and both the top limit switches active, it is only possible to operate the top in the closing direction.

If the interruption occurs as a result of a fault, i. e. when the dead center limit switch is activated, it will only be possible to operate the top electrically again when the dead center limit switch re-releases the "close top" operating sequence as a result of the adjusting screw being unscrewed.

If the "top open" limit switch is activated during the top opening process through e. g. adjustment operations, further operation in the opening direction cannot occur once the limit switch is open. If it is wished to resume operation in the opening direction, this must be preceded by briefly selecting the closing direction mode.

If the indicator lamp does not go out when the top is closed, a check must be made as to whether the locking motors are correctly adjusted vertically, i. e. in a position mechanically to lock completely.

If the top moves excessively slow (correct operating time 20 - 30 seconds), the power consumption by the control unit should be tested. A permanent current in excess of 20 A is an indication of impaired mechanical movement.