Checking the output voltage is easy and let's you know exactly what's going on. Adjust output to 28.8v on the 60amp unit.
If your dash gauges are up to snuff (voltmeter) couldn't be any easier GO/NO GO. I would go a step further and make sure ALL connections are clean and tight . As been stated over and over, Grounds connections are important !
The other half of the circuit is.? ? You guessed it the positives and there are a few to work out.
Starting in the battery box with batteries, label / tag / document all connections (cell phone snap shots) before disconnecting,
Inspect, clean posts, terminals, lugs, jumpers, hardware as needed (leave disconnected for now)
Offend neglected, loose and corroded... Follow cables (POS & NEG) to where they connect up to... be it shunt (not a fuse, NEG) or Positive to feed thur, in and out, This can be a little bit of a mystery. They pass thru the battery box to the other side (inboard side of box and right frame area)
These are important parts as they are primary conductors to the system. Basic big nuts & bolts & washers couple of insulator & RTV goop. I suggest a very close inspection or break them down, clean-em up and reassemble. (pay attention to insulators and torque or see the TM's)
It's then down to the starter for another photo shoot and clean up. This is an area that has seen every place the rig has been... MUD & CRUD.
Some rigs follow a little different positive lead from starter to alternator or control box. Work the one you have to be sure all is nice, clean and tight.
It's your choice to get dirty NOW or do it on the side of the road later, IMO. Once done and knowldge learned on this system... good for another thirty years. Once tight, nice and clean one can seal for waterproofing - corrosion control.
Paying close attention to any metal hold down brackets / side of box or bottom of that custom seat base that could make contact if batteries shift when doing air operations. And of course the + & - all correct.
And as a free added bonus if you got this far... I measure - set charging voltage (60 Amp alt's) AT the batteries. This eliminates any voltage drop ( yes small ?) for true battery terminal voltage as read on a digital meter. Tenths of volts make a difference in wet cells batteries as to charged or less than.
This is a very simple electrical (overall) rig. Don't let a loosy goosie, corroded, busted wire connection stop one dead in their tracks.
Common tools, wire brushes, safety glasses, gloves, baking soda, paint, RTV goop, TM's (who has that ?? ) a beer or two...Good to GOooooooo, CAMO