Ford 3910 wont start

[LogHvnracer]

Have a 1987 Ford 3910 diesel. Relatively low hours (718) for year. Recently when running (or turning switch to run) both gauges on the dash started to go in opposite directions. For example, if fuel was 1/4 full, the gauge would show 3/4. Started tractor yesterday and gauges were showing wrong but it ran fine. I can turn switch to off position and the gauges stop working but tractor still running since only can kill engine when I cut engine off when I pull out red knob. I think this may may be normal. I turned off tractor to put something in shed and now it won't restart. It does nothing when I turn switch. No clicking of starter...nothing.

Battery is about 5 years old but shows 12.6 to 12.7 volts with battery wires attached and 13.0 when unhooked. I charged it for several hours just to be sure and battery charger shows it has a full charge. I had starter completed overhauled last year with new solenoid switch. I have cleaned both cables and battery posts.

I read where it may be the safety switch for the high/low transmission but why would the gauges run opposite? I am thinking it has something to do with a ground connection. I have checked those and cleaned but maybe a bad battery wire with corrosion in it?

Was planning to take battery and starter into town to have checked but any suggestions?

Thanks.

 

[Harry in Ky]

Probably two separate problems. 3910 should have a neutral switch on the hi/lo shift rail, and one on the pto lever. Both are wired in series between the key switch and the starter interrupt relay located on the firewall somewhere behind the battery.
The gauges are powered through the key switch as well, but shouldn't be affected by the start circuit. Have you pulled the gauge cluster out and looked behind it for a possible mouse nest? Amazing how many gauge problems the little critters can create.