So I'm trying to impress the boss, long story short I need to fix our 2013 cat 2.2 powered stump grinder. It's not charging, the battery is fine, connections on batt and alternator are fine, accessory belt is tensioned. Fires up great, but charging light doesn't go out and s 11.5v at the batt and the same at the alt. Now if I hit the field wire with 12v it starts charging. My question is where does the field wire go? Is it a relay? Fuses are good btw. The field wire only gets voltage for a second right? Were do those magic pixies come from??? Tomorrow I'm going to check all connections on the back of the ignition. Thanks guys(and gals)!
Usually the wire will get power from the ignition switch, may or may not be through either a light bulb or diode, either of which might be bad.
i have 2 small john deere powered peices that excite with a diode in the loop took me a minute to figure it out , i have a caterperkins in a sullair compressor i will be by it tommorrow I will take a quick look and see what it has for this guy if i see anything at all , im pretty sure it has a self exciting alternator though i dont recall seeing any diodes on it when i was fixxing it from being run over by a landfill compactor