I had the same issue with my 91 300sl back when this thread started in 2010. I have since sold the SL.

I suppose the 91 and the 92 are the same.

The problem I had was caused by false trouble codes which prevented the top from going up all the way. I remember that it would go to about half way and stop. I also remember the blinking switch.

You may find the procedure back in this thread.

It involves finding the connector under the hood on the right side near the fire wall. There is a cap over the connector that you remove. You then jumper two of the sockets together for a specific number of seconds then the light on the top switch will start blinking. you need to count and record the blinks. You jumper again and count and record the blinks. You do that until there are is more blinking. Somewhere in this forum on the 300SL top is a chart posted that tells what the codes mean. Once you know the codes you go back and clear each code. Once I codes are cleared the top on my SL started to work again. I think you have to start the engine and drive the car a short distance for the top to start working.

If you clear the codes and the top does not work you need to go through the code checks again to see if one code tell you if you have a bad switch in the system. I think there are a gazillon (maybe 15) limit switches that all have to work. There are also a number of other sensor that are involved.
Sorry that I can not be more specific but at least you get the idea.

If you can not find any help in this and other threads on the topic let me know but I think I gave all of my notes and diagrams to the guy that bought the car. Bob Terry is an expert on this issue. You may want to send him a private message or he may get copied on the thread.

Good luck. I loved my 300SL! I sold to guy in Germany.