I killed the battery by leaving the lights on, and connected jumpers to the + terminal in the front of the truck and the - to the engine lifting lug in my 85 diesel MM. It charged for about 20 seconds, started to smoke under the hood. I disconnected the jumper cables and looked for the source of smoke, but couldn't find it. I used thick jumper cables with more than 1/4" diameter copper and jumped plugged it in to a running car battery.

After the smoke all cleared and the places that I clamped to on the truck cooled down, I noticed that none of the cabin lights turned on. I tried connecting the jumper cables again, but it didn't seem to push any more charge through, or light up the cabin. All of the fuses in the fuse box are still good, but nothing works.

The other perplexing thing is that when I removed the truck's battery and measured resistance to the + charging terminal in the front of the truck, it had no resistance. The same was true with the - battery terminal to the engine. So the positive and negative cables in the truck have continuity. I also confirmed this by getting the battery charged and putting it back in the truck. The + terminal in the front has 12.6V, which is the same as direct to the battery. I would expect everything in the electrical system to work, but nothing does. I also questioned whether the battery was somehow not giving enough current to actually run something as small as a dome light, so I removed the truck battery and replaced it with jumpers to a running car, but nothing came on.

My question is, are there any fuses in the charging line? If so, where are they and what do they look like? I am super confused at this point because I haven't been able to isolate the problem. I am not sure if I need to start looking for shorts. I would expect that a big short in a hot line would cause a bunch more smoke, and make itself obvious.

Thanks in advance,

Chris