I had an issue with my top last year and at the same time my roll bar stopped functioning. When I cleared all the faults for my top and had the top working again, the roll bar still did not work.
Any suggestions on trouble shooting this or checking for faults? The lights on the switch come on when I start the car but no lights in the switch come on when I am hitting the button up or down.
1991 500sl

 

I would begin by checking the diagnostics for the roll bar controller.

The procedure is to read the first code, record it, erase it, and then repeat for additional codes until there are no more codes. Then try the system and go back and read codes to see which ones returned.

To read a code, you must first trigger it by shorting the diagnostic socket of the system you are checking to chassis ground for 2 to 4 seconds. A moment after the short is removed, the code is output in the form of a series up electrical pulses. You'll need to connect a device between 12 VDC and the socket to view the pulses. It is common to use an LED in series with a resistor. I like to use a particular LED from Radio Shack because the resistor is built-in and I can just use the LED by itself. The part number is 276-209.

Erasing a code is like triggering a read. Immediately after reading a code you erase it by shorting the socket to ground for 6 to 8 seconds.

On your 1991 SL the diagnostic socket for the roll bar is #7 on the connector, socket #16 is 12 VDC, and chassis ground is socket #1.

 

Ok, I did what you recommended. The codes which showed were 7, 5,3,1. I cleared all but the "1". This one will not clear. I tried many times with no success. Roll bar still is non functioning. Do you know what the "1" means?