I don't mean to hijack this post, but i'm having the same issue with my '95 E300. I have done the X27 test and all is good. I even took it one step further and found a 4 way connector (what I believe to be X49/2) and it worked from there. I manually bypassed the NSS (S16/1) and that didn't help. All my fuses look good. I am thinking it may be either K38 or possibly the ignition switch itself. Is there a way to isolate/test K38 before I have to pull the instrument cluster?

Thanks!