Falco Nero

Hi all,

I know that pretty much everything has been written about issues regarding soft top not opening / closing properly but let me just explain my specific case and the result of a first check from my side.

I just got this R129 in a sorry state, wanting to save her. When I hit the red button to open the top, the windows are going down as expected, but once they are fully down, the button starts flashing and the top won't move.
Furthermore, the roll bar up-and-down button won't move the roll-bar, only a sound relay tick is heard when I tap it, either opening or closing. Same thing happens with the softtop button IF the car has engine off - loud tick on opening or closing but nothing moves. Instead, if the engine is ON, softtop button would trigger the windows downward movement and then stop there, flashing.

I already checked the fuses in the trunk and in the engine bay. Checked the fluid level in the hydraulic pump, it's OK. What can I check further from the electrical part? I would like to test the roof ECU but still have to investigate that part.

Furthermore, I am pretty sure one or more cylinders are shot but in that case che movement should be triggered at least, with the car then unable to complete che process or so, but I would hardly think it won't move at all.
Chances are the car has been left standing quite some time.

Thank you in advance for all your precious insights!
Regards

mahunt

Have you tried cycling the top manually?

Do you have a MB dealership nearby that can scan the top controller?

Do you have any persistent trouble lights after the engine starts?

When my top cylinders started leaking (catastrophically in the end), the top still operated and most importantly, so did the roll bar. Do you hear the top pump trying to work?

Falco Nero

Hi, thank you for your reply!

What do you mean by cycling the top manually? I just manually removed the hardtop and then closed/opened the softtop manually because any other automatic operation was out of order.

Regarding the Mercedes dealer, there's something closer to the city.

No lights on the dash are on

When I operate either the roll bar button, or the red roof button, a sound ticking (like a relay) is heard, but nothing else. I can't tell if the pump is getting power - will have to check that.

mahunt

Sounds like it's time to have someone scan the controller.

Oldmansl

AT LEAST TRY THESE RESET STEPS THAT WERE SHARED WITH ME AND SOLVED MY ISSUE, HOPE IT HELPS YOURS TOO. RESETTING SOFT TOP SYSTEM





**TO RESET SYNCHRONIZATION OF WINDOWS AND SOFT TOP**

When you disconnect and reconnect the battery on a 2000 Mercedes SL500, it can sometimes cause the convertible top to lose its synchronization or reset certain systems, which might lead to the issue you're experiencing.

Here’s a step-by-step guide you can try to reset the convertible top system:

1. **Fully Lower the Top:** If possible, manually lower the convertible top completely. If it doesn’t go down automatically, you might need to do it manually by disengaging the hydraulic system or using the manual override in the trunk. The owner’s manual should have instructions for this procedure.

2. **Reset the Windows:** The windows are part of the top operation sequence. To reset them:

- Lower each window completely.

- Hold the window switch in the "down" position for a few seconds after it reaches the bottom.

- Raise each window completely and hold the switch in the "up" position for a few seconds after it reaches the top.

3. **Resynchronize the Top:**

- Turn the ignition key to position 2 (do not start the engine).

- Press and hold the convertible top switch in the "open" position for about 10 seconds.

- Then, press and hold the switch in the "close" position for about 10 seconds.

- Try operating the top normally to see if the system has resynchronized.

4. **Check for Error Codes:** If the above steps don't resolve the issue, the system might have stored an error code when the battery was disconnected. If you have an OBD-II scanner or can access one, check for any codes related to the convertible top system.

5. **Check the Fuses:** Inspect the fuses related to the convertible top system to ensure none have blown during the battery reconnection.



If these steps don’t restore full functionality, there might be a more complex issue requiring professional diagnosis, especially if the hydraulic system or control module was affected by the battery disconnection.



Quote fromMBWorld: 2001SL500 owner's manual, operations section, soft top subsection. Full sentence starts 'To lower the soft top, first...' (2001 OM, pp147).

with parking brake on…

'Press ^ side of power window switch until the window is completely closed and hold for an additional 2 seconds. Repeat procedure for each window. The automatic full opening procedure of the windows should now be restored.' (2001 OM, pp117, operations, power windows)

mahunt

An OBD-II engine scanner (I have one) will not read the: transmission, chassis OR power top computers, just the engine.

Bismarck

My 1996 R129 has had a similar problem if left inactive over the winter, but is curable by partly removing the controller and reseating it with a firm shove. A free fix if it works!

Falco Nero

Hi, thank you for the thorough list of troubleshooting tips.
Here's what I did:

- Fuses are not blown
- There is hydraulic fluid in the pump - approximately at level
- The windows do go up and down, and do the half-inch movement when door is opened/closed - this is a good sign at least
- The roll-bar is not moving when pushing the button on the center console
- The soft top opening/closing button, when operated, just moves the windows fully down and then starts flashing
- There are NO warning lights on the dash
- The window reset procedure with window buttons down and then up does actually resent the 0 position of the softtop but won't solve the problem.




Thank you for your insight. With "controller" you mean the roof ECU? Will try to do it.
Is there a way I can test it so I can be sure it is the culprit?

Many thanks in advance!