1990 300SL.

Apologies for long post.. tried to be succinct.

What I gather is usual soft top weirdness am looking for advice. What I have discovered abd done so far when I try and raise or lower top it hangs after making clicks and whirring noises. No other action Took out the rear panels and po had unplugged the roll bar ecu. Plugged it back in.

Built a diagnostic tester
tested pin 10 Got code 23 = roll bar ECU fail.
pin 7 (roll bar ecu) = code 8 = warning lamp..

Being clueless I picked up a second roll bar ECU on ebay Bad news same error code from top ecu, (23) good news new roll bar ECU has no codes but I have not driven the car with it installed. (btw the roll bar warning lamp comes on when I switch on the ignition so bulb is good.

Roll bar switch in dash does nothing but flashes red twice when I switch the ignition on. Does not operate the roll bar or turn on the motor or anything tested switch with a multimeter and it appears good.

If I hotwire the roll bar solenoids and the pump I can get it to raise.. (good thing I think)

After I raise the roll bar I can lower it by initiating the soft top switch. (good thing too)

Started to study the ETM and this is where I could use some help. From what I can tell the roll bar ECU tells the to ECU " I am OK" If it does not do that the top controller errors and stores code 23.

Wiring according to ETM for RB ECU (N53)

RB ECU (N53) pins 5+6 ----> Top ECU (N52) Yconnector pins 11 and 12.

I get output approx 5V output voltage from the RB ECU Ignition on or off.

at the y connector I get no voltage on pins 11 and 12

BUT if i look at the ETM for the soft top it tells me that pins 11 and 12 on the y connector are unused.

Am going to test continuity next but I cannot figure out the ETM. Could this be errata? Why would it say that pins 11 and 12 are unused? Perhaps I am reading it wrong? Anyway I am hoping someone has dealt with this.. from watching the MBcluster video it sounds like code 23 is pretty common.