Convertible Top - System Modifications
REF. NO. 77/34ATO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE: July 1994 (supercedes S.I. 77/34, June 1994)
Revision: Supplemental Information for Bara Electronic Tester included.
SUBJECT:
MODEL 129
ROADSTER SOFT TOP (RST) SYSTEM MODIFICATIONS
As of January 1994, starting with chassis end number 097252, the power soft top's control and hydraulic Systems have been modified.
The modified hydraulic and control systems are recognized by the following:
Soft Top Hydraulics
1. New left RST valve block.
2. New right RST valve block.
3. Roll bar valve block has been eliminated.
4. Function of the roll bar has been integrated into the right RST valve block.
5. Due to the modified RST valve blocks, the routing of the hydraulic lines has been revised from previous versions.
Soft Top Control
Following limit switches have been eliminated:
1. Soft top bow "closed" switch (A23s1).
2. Left soft top compartment cover "closed" switch (A24s1).
3. Left soft top compartment cover "locked" switch (A24s2).
4. Right soft top compartment cover "closed" switch (A25s1).
Additional Components
A reed contact switch (S84/4) in the windshield crossmember, with a respective magnetic plate in the soft top front section (arrow, Figure 1).
Modified Switch
Description of switch (584/4):
Up to chassis end number 097251, S84/4 soft top "overhead" switch (Differential operation). As of chassis end number 097252, 584/4 soft top "closed" switch (Reed contact).
Modified Control
During the closing phase of the soft top, just shortly before the soft top contacts the windshield cross-member, the reed contact switch (S84/4) sends a signal to the power soft top control module (N52). As a result, the RST/RB hydraulic unit (A7/5) interrupts the operation for 0.7 seconds, causing the latch pins of the front soft top latches to fall into place.
Should one of the latches not release during the opening phase of the soft top or one of the two soft top "locked" switches (S84/1, S84/2) not open, the signal sent from the reed contact (S84/4) remains at the power soft top control module (N52). As a result, the power soft top control module (N52) stops operation of the hydraulic unit (A7/5), which relaxes the soft top, allowing a possibly a stuck latch pin to free itself.
Note:
The latch pins of the soft top frame do not engage in the center of the front latches as before (arrow, Figure 2), but initially and momentarily into the rear section of the front latches (arrow, Figure 3) only. Thereafter, the soft top hydraulics pulsate, thus moving the soft top forward and the latch pins subsequently engage completely into the front latches.
Additional Changes and Innovations
During the unlocking or locking of the hardtop, the side windows are now lowered or raised as necessary. Should the hardtop be improperly locked, the warning chime will sound for a max. of 10 seconds, or until the vehicle is stopped. Should the vehicle subsequently continue to move, the warning chime will not sound, but the light in the power soft top switch (S84) will continue to flash.
Soft Top Diagnosis
^ This new soft top version may be diagnosed with the Hand-Held Tester (Module 01/94).
^ Diagnostic Manual, Body and Accessories, Volume 2, Supplement 7, Section 11.3 applies to the new system.
Supplemental Information for Bara Electronic Tester
If you own a Bara Electronic Tester, please contact the MBNA Standard Equipment Program group and ordering information will be provided for the updated module and cable diagnostic set. The diagnostic set is available under the vendor part number: FA 940 17 R 129.
Parts Information