I hate unresolved forum threads, so I wanted to close the loop up on this one. I had purchased a used but "tested and working" ECU from a vendor so I looked for other sources of failure. Unfortunately, I replaced the DESS post, ohm tested all wiring harness to MPEM and ECU and even purchased a Candoo system to read faults. I continued to have the intermittent Key-Off power, Failure to read ECU, and various odd faults that would then disappear if I let the ski sit for a few days, then return once ski fired up. Took the ski to a marine tech specializing in PWC and found the ECU to be bad. Most likely the ECU would cool down to stop internal shorts just long enough to startup once, but would then begin to internally short and need days to cool down again. Put a new ECU in, the symptoms immediately disappeared and I can reliably fire the ski up again. It runs fine without the cluster. I actually 3d printed out a cluster mount and wired in some really nice aftermarket GPS speedo, tach and fuel gauges to replace them. Only thing I don't have is the maintenance LCD but I have the Candoo. I just can't shell out $750 for a couple gauges. Thanks.