Hi Bob,
I just went through that issue, no crank, no start, black rectangle. In my case it turned out to be a bad splice in the CAN bus. (Usually, it's either the RCM or the SLA.) If you search for my post, you can see all of the diagnostic steps I performed with the resulting measured values and how I finally fixed it (had to bypass the splice). I give a lot of details which I won't repeat here, but you can ask me questions. Another post to search for is "Pulse module", and ECU problems by 1sweatride. Good Luck, sincerely
Jerry