roll bar and power hood not working-help!

[matt white]

Hi. I have a '91 300SL 24. The roof and roll bar have stopped working. Are they connected in any way. I presume the management system will not allow the roof to work if the roll bar is not operating properly.

The console switch for the roof flashes when pulled or pushed, alas no movement of the roof, not even a click or whirr; silence! The roll bar console switch lights up when starting ingition and goes out on start up but again, no movement.
Does anyone have any clues please, thanks
Matt.

[joeym]

Hi Matt I would have this veh tested by a good tech with tools,as your soft top and roll bar has many updated parts and when you change one ,like the soft top control module you must change valve blocks ect,ect,ect and it can become very costly,if lucky its something like a fuse,pump low on fluid shutting down the system or a micro switch.joeym

[TheV12pwr]

If your rollbar is 'up' position,something must have triger it!
Need to reset the control unit.
I do it by playng with the soft top switch and rollbar switch at the same time.
Also try pushing the rollbar down and push the rollbar switch 'down' at the same time...worked for me!

[speace]

Mine started doing that this spring. I removed the hard top and closed the soft top. The next time I tried to retract the soft top it just blinked at me and the roll bar was inoperable as well.

I trird several things and finally took it to my shop since it was time for maintenence anyway. They said there was nothing wrong and indeed, all was working fine when I got the car back!

When I asked how this could be, they replied that the early 129's tend to just lose their programming occasionally and just need to be reset.

Exactly how they reset it I don't know, but I suspect that they disconnected the battery, or disconnected the power from the computer module for a time to let it reset itself.

A while back, my roll bar stopped working and I disconnected the battery for 20 minutes and when I reconnected it and re-synchronized the windows everything was fine.

Yes, the top and the roll bar use the same computer module. Synchronizing the windows is accomplished by rolling them up and down a few times.

There are several threads here on this subject that can be located wth a search.

I hope this helps.

[bobterry99]

Diagnosing these top problems can be very simple. Your soft top controller probably has one or more diagnostic codes stored which will tell you the exact problem. To get the code(s), turn the ignition on but leave the engine off. Locate the car's main diagnostic connector (X11/4) near the left strut mount.

Take a paper clip or length of wire and connect socket #10 of the connector to socket #1 or chassis ground for 2 to 4 seconds. After a second or two the lamp inside the top switch will flash. Count the flashes to get the code. Repeat for the next code and so on. Report back with your findings.

If you go to this link you will find a picture of X11/4: http://www.mbnz.org/forums/forums/thread-view.asp?tid=1168365.

[matt white]

Hi, thank you all for your advice. To start, I have disconnected the battery for half an hour. This did not correct the fault, although it has stopped the hissing sound from the driver's door speaker on opening the door, thanks for that.

Message to bobterry99- Thanks for your advice. I will attempt to short socket 10 to socket 1 tomorrow morning. One question though; your sentence (Repeat the read procedure until you have all of the codes. You implicitly know you have them when the sequence of codes begins to repeat). Please excuse my ignorance here, When you say repeat the procedure, do you mean then short socket 9 to 1 then socket 8 to 1 etc, or just repeat 10 to 1 again

[bobterry99]

Just repeat shorting 10 to 1 for 2-4 seconds, Matt.

[matt white]

message to bobterry99. Thanks again for your advice. I shorted 10 to 1 with ignition on & engine not running. Console switch lit as it was plugged in for about 4 seconds, unplugged short and waited for the flashes. Alas, no flashes. I repeated this, still no flashes; unless there is a code for 0.

I read on another person's comments that they suggested disconnecting the battery and touching the two terminals together for 1 minute to shed the volotile memory. I am a little wary about trying this and losing codes/information and getting further in the myre; what say you?

[bobterry99]

Matt, have you tried again with shorting 1 to 10? Maybe try for a little less time. You should get at least one flash. While the short is in place the light is on, when it is removed the light goes out, and after about a second the flash(es) come...

There is no problem at all with removing the battery terminals from the battery and shorting them together. I believe the idea is to discharge the capacitor which provides voltage regulation to the always hot circuit #30. It is worth a try, though I think if you were to measure the potential between the terminals just before shorting them you would find no voltage present anyways.