2007 Speedster Wake DESS problem. Eratic

[olekwj]

Guys, ive read for days on the DESS problems. Ive tested the DESS post and the key and both are good. What happens is, 95% of the time there is no issue, I install Dess key and get my beeps and everything powers up as its supposed to. But every now and then I install key and nothing, no beeps, no power to anything. Boat was in my driveway and I installed key and got nothing, so pulled it off and on probably 20 times and nothing. So I start crawling all over the boat, checked battery voltage at 12.7, pulled on wires and checked fuses all over, still nothing. all this while key was on hoping if it was a loose wire it would make connections and beep at me. Gave up for the night. The next day I pull post and key and bring inside to test, all tested out good. Installed back in boat and installed key and nothing. Left key installed and started messing with wires under driver dash by what I guess is the MPEM or fuse block and was done in there and closed the dash lid and was walking away and I get beeps and power up on dash probably 20 seconds after I closed dash. Very eratic, like it just was waiting for something, not sure if it has anything to do with the wires I was pulling on a minute earlier or not. Real question is, What should I do? go ahead and replace post and key just in case, or do I need to be looking at an MPEM or what? Im confused on this boat whats what, there is a siemens ECU on each motor, then a fuse type MPEM looking module for each engine next to solenoid at each engine, then the same looking module like MPEM by engines, up in dash behind steering wheel. Are these modules MPEMs or does this boat only use the ECU's attached to engines? Btw, the day this all happened, I took boat to the lake and it worked all day perfectly. But im worried one day ill be out in the water and the key will just not do anything when I install it, and I wont have a clue what to do. So id like to find out what is the actual problem.

 

[gazzaskirepair]

I e had those days too frustrating not to know what caused it to beep again
I would check the Post connector connections for corrosion as well as the module behind the dash
Would need to check the wiring diagram to see where the Dess is wired into and do a continuity check of the ground wires and positive to the Dess post