M1088 with 4 (Four) leads into the battery box

[Ronmar]

With the picture above of the 4 wires coming un the battery compartiment....can Someone specify which is the 12 v (i know super short is 24v, and clarify the training 2 please

It is impossible to determine from the photo which is which, except that short wire is probably a 24. You need to hand over hand them or use an ohm meter and check them one at a time.

one 24 runs directly to the starter+ terminal
one 24 runs to the 24 batt terminal on the polarity protection device
The one 12 runs to the 12 batt terminal on the polarity box.
the ground runs to an instrument shunt next to the polarity protection device and on to the starter negative terminal and the main chassis ground strap.

The polarity box is inboard of the spare tire, and is easiest to access if you lower the spare tire so you can crawl in there… The inst shunt is just to the rear of the polarity box…

 

[Third From Texas]

Typically, if they were laid in order where they came off...

Starting at 2:00 (inboard left) will be the 2x 24v.

The 11:00 (inboard right) will be the 12v.

The 5:00 (outboard right) would be the ground.

 

[Mario]

With the picture above of the 4 wires coming un the battery compartiment....can Someone specify which is the 12 v (i know super short is 24v, and clarify the training 2 please

People tend to overthink this and it makes it confusing.

Think of what's happening, and perhaps it'll make things simple(r).

If your connections are still in place, you have 2 wires going into your Nato slave connector. This makes it dead simple as one wire is ground and the other is 24V. From there, you only have one other cable, and that's your 12V, which connects between the 2 batteries and it doesn't matter which one.
That's it -- you're done.

If you have 4 batteries, you simply double them up. Imagine stacking batteries one on top of the other and connecting each post vertically.



If you already took the batteries out, it's just a few more steps.
Nato recep is easy because it's just 2 cables and one is ground, and the other will go to 24V.
Figuring out the 3 connectors on the back, left side goes as follows:
1. Typically, the longest cable is ground. To verify, make sure everything in the truck is in the off position. That includes the master switch and lights. Use the multimeter on continuity or resistance setting and have one lead on the frame, and the other one on the battery terminal. Only ONE connector will give you zero (or very close, as in less than 1 Ohm) or resistance. If you have a continuity setting, only one cable will beep/buzz. That's your ground.
2. The 24V cable is typically the shortest one into the box. Using a multimeter check continuity on that cable to the starter. The starter will have 1 big wire coming from the battery. Again, you're looking for zero ohms or listening to the buzz. You might need to use a piece of wire or even a household extension cord to 'extend' your multimeter leads from one side of the truck to the other.

When doing this testing, it's always a good idea to test all the wires, to ensure that your results are ONLY TRUE on ONE terminal/wire and no others.
That ensures that a. you don't have any shorted/exposed wires, and b. that you didn't screw up and got a false positive reading.

Hit me up if you have any questions.

 

[Third From Texas]

And the cable terminal clamps also have two sizes.

Ground is the smaller.

So the longer cable with the smaller clamp should be the ground.