Combines Goofy monitor

Sounds like when you turn lights on it draws heavy on the electrical system. This can effect other circuits, possibly the electronics. Also check to see how these circuits are supplied AND grounded. If one happens to ground through the other, like a light bulb in an instrument, it could cause the monitor to go screwy. I had this happen once in an autotronic MF 3120. Had a bad ground on printed circuit of dashboard, flashers or signal lights would effect 4WD and differential lock through autotronic. Try turning a corner with your signal light on with all four wheels and differentials locked. Good luck, hope this helps. Sorry, don't have any experience with this model. Stuff like this can be a real headscratcher.

I have the same problem with 8570 on oil presser light, the tach has stayed rock soled. Has only got bad enuf turn it off 2 times.The oil presser run around 50 and drop to around 25 at idol, so I have thought that it is not the sender. The volts on the volt meter is around 13 volts, it dosen't seme like voltage problem. On the 8570 there is a ground wire the same size as the 12volt line to the cab from engine chasiss. Sorry for no help I gust haven't come up with a start place yet even. swtvid