I'm having trouble with a no start. I think it is in the key switch-but not sure. Everything was working until I repaced a headlight, then the system went dead. Is the voltage to the switch supposed to be 24 volt or did they step it down? Do the gauges and headlights use 24 volt? The electrical diagram I use shows everything at 24 volts, I THINK. It's an old machine (1979)and probably does not have the original wiring.
As far as I know, everything is 24 volts. I'm not much of a mechanic, and even less so over the internet, but, when you turn the key switch on does everything else work as it should, and are you just getting no cranking at the starter, or do you get no results from turning the switch at all?
No results from turning the key plus all electrical systems are dead.
If I recall correctly, there are two small solenoids and a set of three circuit breakers mounted beside the engine, just above the starter itself. I'd begin by checking there to see if you have juice. (Sorry, I can't tell you from memory exactly what's connected to what there, but the wires are there to follow.) Ah. Here's a link to the online parts catalog http://www.casece.com/wps/portal/casece/partscatalogtutorial?brandsite_brand=CaseCE&brandsite_language=en&brandsite_geo=NA It won't post a link directly to the page, but if you go to 680G, and then to the electrical system, the picture of that area is found under, "086 Electrical System front harness and connections."
On the some of the dozers Case would wire the headlights in series - using 12 volt bulbs on a 24 volt sys.