electrical question
 

Hey fellas...have a unique situation here that I need some advice on.

2004 Mule 550

So its a long story, but I drove 3 hours on my mule to my D7 cat dozer. One of the 24 volt batteries had been acting dead so I brought a jumper cable box with me that I had successfully used for the two previous days. I hook up the jumper box and the dozer barely turns over. The option of driving back to my truck and bringing it to use to jump the dozer would have taken the rest of my day, so I looked at my running mule and thought what if I hook up jumper cables to the mule and use the jumper box at the same time. It was that or lose a whole day of work.

So with dread in my heart, i slowly walked up to my running mule with the jumper cables in hand and connected them to the battery. I placed the other end of the cables to the 24 volt battery that was dead. To my surprise, the dozer cranked up finally and I disconnected the jumper box and mule and turned it off. I knew it wasnt a smart decision when I did it, but I literally had no choice.

That evening when I got back to the mule, it would not even act like it had a battery connected to it. I turned the key....starter does nothing. I then tried just the LED headlights lights....nothing. Not even a flicker. That told me that no voltage is even reaching the lights. The battery voltage read 12.5 volts, so I checked the inline fuse that connects the two white wires and it looks fine.

I finally gave up finding the cause. In a desperate attempt to avoid walking 4 hours at night on the ranch, I got the jumper box cables and grounded the negative cable to the engine and connected the positive cable to the positive post on the starter. I then turned the ignition key and it started right up without a problem. I disconnected the jumper cable box and drove back to the truck. The LED headlights would only flicker while driving.

Sooooooo....it sounds like the ignition works fine since I used it to crank up the starter when it was connected to the jumper box. I THINK the battery itself is ok since it reads 12.5 volts. The starter seems to be ok since it worked to start the engine. There is obviously a break in the circuit between the battery and wire harness.

I gave the wire harness a quick glance that evening looking for a burned wire or black marks somewhere, but didn't see anything. Could someone give me a checklist of some sort to start looking for where the voltage is not connected to the wire harness? Thanks fellas.