I'm new and don't know how to start a new thread. I just purchased a M915. It runs great, but much have had a lot of electrial problems, bcause it has a new alt and some of the gauges were wired wrong. Everything is working now except the tachograph. The gauge is new with 59 miles on it, plus both senders and new wiring. However it won't work, tach or speedometer. Anybody have any suggestions?