i have a 1996 kenworth w900b that the speedo and tach stop working in, either one or the other will work, but not both at the same time, differs each time you run the truck ??? looking for a common problem with this possibly, any help would be great
You can answer your own question with a little thought;
Hint- grounds, electrical plug, MAYBE a power source, but have my doubts. I had a 1996 W900, never had that problem, but wondering if a sensor would be related to both speedo and tach. My advice would be to check ground, then plug in dash behind the two.
You might also try adjusting the sensors. The tach sensor will be on the flywheel and the speedometer sensor will be on the tail shaft of the trans., unplug the sensor wiring, loosen the jam nut then screw the sensor in til it touches then back it out just enough to where it doesn't rub, as it picks up by magnetic force, when your done just tighten the nut and plug back up. Good luck