I wanted to shoot you a quick message. It seems you are the M-Craft guru!
I live in Hawaii and am very limited on wake-boat support out here. I'm having a problem with my gauges. I have an '04 X-80 STS. The speedo and both tachs are inop. The Speedo is wheel based, not a pitot tube. All grounds have been triple checked, both engine harnesses have been replaced. The ecu's are brand new on both engines and read find when plugged into a rinda system reading there outputs.
Once in a while oil temp and water temp gauges shut off, but normally they all work. I have unplugged individual gauges and nothing changes. I have two MMDC boxes, but dont want to replace if it doesnt sound like this is the issue? Do you have any other ideas? I have read that gauges go haywire, and MMDC boxes fail... I purchased boat from Las Vegas area, so there were freezing temps in that area....but without water coming in from speedo, i wouldnt imagine that is the problem?