Since Nordic used these gauges on a lot of their boats, I hope maybe one of you can help. My tach on the port engine is not registering, nor is the hour meter working. I contacted Medallion last year and they said that the gauge might be bad...so a couple hundred later, new gauge...no worky

Ok, so I talk to another tech rep at Medallion, he says that the system sends the digital signal throughout the wiring loom and that the gauge determines what it is reading, he suggest that maybe the connector for my tach is bad...switch connectors with another gauge and check it. Still no worky, so I go one step further, I switch tachs...the new one works on the starboard engine, the old one doesn't work on the port. Medallion pretty much said "good luck". SO, it's got to be either the signal going into their little computer or the computer itself, can anyone help me diagnose this from here?