This circuit has an unusual design characteristic. The fuse indicated is the only one that will blow when the generator's output terminal is accidentally grounded, but there is a second circuit that comes off the battery before that 100-amp fuse. and feeds the ignition switch circuits. Part of that feeds the generator's internal voltage regulator, and it feeds the dash warning light which is the "turn-on" circuit for the voltage regulator. That means even with that 100-amp fuse blown, the generator can still work once the engine is running, and it will supply all the otherwise dead circuits. Those circuits will be dead with the engine not running, but will work with the engine running. If that is what you find, to verify the 100-amp fuse is blown, check for battery voltage on the generator's output stud with the engine off. If it's missing, that fuse has to be blown. In many applications they're designed in such a way as to make simple visual observations impossible.
If you still need to troubleshoot the power supply circuits, these first two diagrams are from Toyota. These look like they're going to be hard to read, so the second two diagrams are from an aftermarket source. Non of these reproduce well. If necessary, I can repost them for you split into the separate sections I pieced together. That will let me make them bigger, but they'll be harder to follow. You might have better luck copying them into a typing program where they can be enlarged for viewing.
Images (Click to enlarge)
May 9, 2021 at 7:37 PM
