It could be related, we have a 91 Eagle. The speedometer worked and after they put new heater hoses on it a couple weeks back it went wonky. I think they knocked something loose. Was at 120 mph then would work, now it just goes from 120 back to 100 when running and nothing else. I'm thinking close as those 2 are might be something similar. I'm having the mechanic look it over when I go back cause it happened there. But for us we can use the Tom Tom if we have to it has the speed on it.
I will be interested in what you find out cause I don't want to lose the tach for sure, at all and will keep the info in case we have trouble.
Also there is an American Coach forum and another called irv. forum. I get help from all 3.
