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View Full Version : Faulty Speedometer/Tach0meter


Paul
08-11-2016, 06:29 PM
Recently purchased an H3-40 Marathon Coach- Having issues with the speedometer and tachometer.
It doesn't work- stuck at the current mileage. Any thoughts/suggestions??
Gil_J
08-11-2016, 08:03 PM
What year is your coach?
Paul
08-16-2016, 04:35 PM
its a 1993
Gil_J
08-17-2016, 06:49 AM
I'm pretty sure that even in 93 the speedometer and tach are driven by a signal from the DDEC. The actual speed sensor may be on the transmission, but the signal comes through the DDEC. If they both failed at the same time I would suspect a communications problem and look first at the wiring cinnections.