My top wont come down Damn it!
 

I have a 91 300SL. The damn top is stuck up. When I push the button forward i can hearthe motor run and pull the top and try to close it more, ut when i pull the switch to open the top the stupid light blinks at me! Ive checked fuses and everything I could think of. PLEASE HELP! what else can I check and were else is there sensors? Thank you all, Awsome site!

One possiblity is on a 91 there is a switch mounted inside the door on the bottom, which are closed when the windows are all the way down, it's possibly an adjustment of the striker for one of these switches(there is one in each door).
Try rolling up the windows using the console switches, then try to lower the top. If the windows both lower, then everything stops working (and the top switch starts to blink) then I believe that one of these switches is the problem.

Gilly

Thank you for your reply, The windows don't do anything with the top. I mean, If the windows are up or down the light just blinks. When the windows are up, and I try to lower the top, the windows do not come down, Should I still check the switches in the doors? Any other sensor/switch? Thanks agsain.

No, the switches in the doors that I mentioned wouldn't be doing it then, so forget that.
What I have done that seems to fix the problem temporarily is to remove the connectors from the soft top control unit. This is the metal box in the storage compartment behind the passengers seat. The is a plastic panel which is easily removed inside that compartment. Remove the panel from the floor of the compartment, the control unit is under there. For some reason just disconnecting the battery doesn't have the same effect as pulling the connectors from the control unit.

Gilly

My car exhibited the very same symptom as satern's. Problem was the switch that detects the top is lowered into the compartment was stuck in the closed position.

Correcting that helped. But it didn't work 100% until I removed the control unit, partially disassembled it, and reinstalled. I think this final fix had nothing to do with taking the control unit apart and everthing to do with removing power to the unit, as Gilly explained.

You might consider checking for fault codes, as explained here:

http://www.peachparts.com/shopforum/tech-help/38215-questions-techs-my-sl-please-read.html

and perorming diagnostics, if necessary, as explained here:

http://www.peachparts.com/shopforum/mercedes-benz-sl-discussion-forum/44939-500sl-soft-top-roll-bar.html

Thank you . You guys are great, I saved and printed the info and Im going to thegarage now. I will post back soon. Thanks

Ok, I DID AS DESCRIBED THE HE SITES PROVIDED AND HERE ARE THE CODES, 26, 29, 30. I did it twice and erased what I could and I still get those codes from the Conv. top button. I took of the cover in the pass side fire wall and There was a burt fuse on top of this red box. There are 2 10 amp fuses there and 1 was burt and I replaced it, Is thos the OVP? I noticed that after I replaced the fuse, The ABS light went out and the car started running weird. First it would not idle but then it seemed to be ok. But I have another question, Im having tranny problems as well. Someone just posted their's and Its the same as mine. Reverse seems to be slipping. But anyway the lights on the shifter dont light up. Maybe there is something blown or disconnected on the tranny therefor the top doesnt know if the car is in park? Just a thought, Please let me know what the codes mean. You guys Are awsome. Thank you for your help. Rick D.

I'm not really sure about the fuses. But the codes:

26 = Operational time limit exceeded
29 = No wheel speed signal from ABS
30 = Operation blocked

Code 30 is a consequence of 29. I believe 26 is also.

Code 29 indicates bad wiring, a problem with the soft top controller, or the ABS controller. Maybe replacing the blown fuse corrected this?

I doubt you do, but if you want to test further you can see if the soft top controller is getting a signal for the wheel speed. Access the controller and remove the "Y" connector (not the "X" connector). Connect a meter to measure AC voltage between socket "9" and ground. Spinning the left front wheel approximately 1 rev/sec. should produce a reading of 2.5 to 4V volts.

What does Operational yime limit exceeded mean? And Would the abs light be on if there was a problem there? I will check out the wheel tomorrow. What about the tranny? What do you think? This is driving me nuts! Is there a way to reset the computer maybe by dissconnecting the battery for a while? Thanks. Rick D

I don't know the specifics of what sets the time limit exceeded fault. I would guess that it is a general fault for a closing or opening operation taking too long to complete.

As for resetting the controller, disconnecting the battery for an extended period should work. But how long is long enough? I think you have to do what Gilly said and disconnect power at the soft top controller.

But hey. As long as you have fault code 29, I think your system is dead in the water and a reset won't gain you anything.

As for the tranny, hopefully someone will weigh-in with some advice. I have the 5-speed manual in my car and know nothing about the automatic.

1991 Soft Top Code reset
 

Bob,

I followed your instruction for reading and erasing codes and my soft top is operational again. Thank you

I found and reset the following codes. 18, 19, 21, 22, 26, 28, 29, 31, & 32. I also drove the car for 10 seconds after erasing all of the codes and before trying the top.

Dan DiThomas

PS: I met a Bob Terry a hundred years ago that worked for TCI, a company that manufactured and erected large Shortwave antennas. Would that be you?

Dan, must have been another Bob! I've never had the opportunity to work for TCI.

Satern, Dan mentions something that might be critical. Try driving the car for 10 seconds and then attempt to erase the remaining codes and operate the top.

And hey. Here is the reference for all the soft top controller codes:

1 = No malfunctions stored.
2 = Limit switch - compartment cover not locked (left)
3 = Limit switch - compartment cover not locked (right)
4 = Limit switch - compartment cover not closed (left)
5 = Limit switch - compartment cover not closed (right)
6 = Limit switch - fabric bow not locked (left)
7 = Limit switch - fabric bow not locked (right)
8 = Limit switch - fabric bow not lowered (left)
9 = Limit switch - fabric bow not lowered (right)
10 = Limit switch - top not locked at windshield (left)
11 = Limit switch - top not locked at windshield (right)
12 = Limit switch - compartment cover not open
13 = Limit switch - fabric bow not raised
14 = Limit switch - top not lowered into compartment
15 = Limit switch - soft top not up
16 = Limit switch - roll bar not retracted
17 = Limit switch - window not lowered (left)
18 = Limit switch - window not lowered (right)
19 = Illogical vehicle speed signal
20 = Hard top installed and no malfunctions
21 = Power top switch
22 = Roll bar switch
23 = Roll bar control unit
24 = Roll bar automatic deployment has occurred
25 = Illogical limit switch signal
26 = Operational time exceeded
27 = Insufficient voltage
28 = No speedometer signal
29 = No wheel speed signal
30 = Operation blocked (code 19, 28, or 29 are present)

10 Second Drive
 

Bob,

Thank you for the codes. You have been a great help.

I read each code twice then erased each code then drove the car forward for more than ten seconds, and then tried to operate the top and it operated.

Quoting an MBNA letter to all dealers dated July 1993

"Increasing, power soft top control modules are being return under warranty which while not defective, have various codes stored in the DTC memory. AMong the codes present are those which suspend soft top operation:

Diagnostic trouble Codes (DTC's) which suspend soft top operation

Model DTC

124.066 3, 18, 20 - 24
129 21, 22, 26, 30

Control modules returned with these codes will not be accepted under warranty.

The following procedure should always be carried out:

1. Recal DTC memory.
2. Erase DTC memory
3. Drive vehicle for more than 20 seconds.
4. Open and close soft top
5. Recall DTC memory again.

Should a problem occur during soft top operation, hold the switch until the indicating lamp in the switch begins blinking. If the previously listed DTC's can be erased, soft top operation is once again possible. In other words, the fault is no longer present. The exception to this is DTC 30, which may be stored again while driving."

Ok. I lifted the car and spun the wheel and I cant get anything. I did as desciribed as far as the "x" connecter and I tried both front wheels and still nothing. I tried with the key on and off too. What does this mean? Is the abs bad? I took off the front abs sensors and there were full of crap, so I cleaned them up good but still had no luck with the voltage. Any Ideas? I will try to drive the car and see what happens, Thanks for the code info, great information. Thanks guys. Rick

Correction to earlier post
 

Rick, you should check the wheel speed signal by measuring AC voltage from socket "9" of the "Y" connector -- not the "X" connector! So sorry.