WOW! What a lot of info... I really can't thank you enough for taking the time to help. This forum is such a valuable resource. I just hope I can repay through helping others as you do.
I'm good with electronics so I will step through your test program after work tomorrow night. Interesting that you feel the ignition switch might be the root cause.
I will report my results.
1994 E320 Coupe (120k)
1990 300SL (BBS,RENNtech adds)
1988 260E Sedan (180k)