90 300SL soft top issue. Wow, there's a new one!
 

Pretty stock 90 300SL, not hits, accidents etc. Soft and hard tops are pretty much totally manual rite now, all fuses ok, no 6 in main and all in rear hinge area. Roll bar fully functional, soft top only slight locking down movement. Red pull switch comes on with ignition, goes out after start, then comes on after 5 sec. or so. For whatever reason, cannot pull the code(s) from No. 10 socket in the diagnostic. Pull switch on console lit but will not flash codes either. Hmmm. Any ideas?? I figure to leave the roll bar up and windows up a little when trying this and that as they should first work in the process when you pull the console switch. If they go down when pulling the switch I"m on the rite track! Controller is the early, 3 input style. Thanks to all, great site! David:(

The soft top's not going to work unless the windows are all the way down.

Gilly, thanks. But, isn't the initial function of the STC to lower the windows and roll bar? And to fully cycle the program once the top is up and locked to allow the windows to full close? I have a 97 SL which does all this, this 90 early SL lets call it does not have the "jump down feature" on the convenience pkg. for totally up windows to open without scrubbing rubber. Don't have as Owners manual so going by memory. Thanks and thoughts?

On the early 129s there is a switch in the bottom of the door that signals to the soft top control module that the windows are all the way down, very simple. Until it has this signal from both windows, nothing else happens, as the glass in the full up position will get broken by the top operations, is my understanding. If window work is done and the small paddles which touch these sensors are out of adjustment you can end up with a non-functioning top. Usually pretty easy to correct, once the door panels are off.
Later ones, they went to Hall effect sensors in the window mechanism, which tells the control module how far along the windows are. It will at least allow the header latches to release. These sensors are also used for the window drop-down when opening/closing the doors as you have noticed. Hassle with them is if the battery is disconnected the sensors have to be resynchronized.

OH but I see what you mean, having the windows up a little and looking for them to go down, yes the soft top module will lower the windows on either car. What I am saying is the top will not operate until the switches in the doors are both closed by the windows being down, at least not on the 90

SL Top 300 early, thanks Gilly
 

I will check the window limiters. I have to take the drivers panel off anyway as the door lock/key in inop on that side. I would think its on the motor/regulator by the old style white plastic stop block on lots of Benz's? Sounds like a microswitch which these cars are full of!
What are your thoughts on not being able to bring up codes on the no. 10 diag. pin. All others work. One to 10, bridge for 3 to 4 sec. then just a very very dim lite. Watching the pull switch for flashes doesn't happen either. Big thanks!