JDH1427

OK. I'm new to this site, but have spent hours and hours in the last couple of days reading threads to see if I could find answers. There were a couple of discussions which people had something going on which at first sounded close to the problem I'm having with my truck, but at some point they start to differ. Thought I'd post myself and hope for some help.

I have a 2004 Silverado LS 2500 HD 4WD 5.7L Gas. I bought it new, and it now has 52000 miles on it. I don't drive the truck daily, mostly on weekends, highway trips, sometimes hauling / towing loads that would be considered light for the truck. It is parked in the garage when it's not being used. It has never given me any trouble to speak of. The stereo and the 4WD indicator light have been a little quirky once or twice briefly, but quickly seamed to return to normal on there own and didn't raise any major concerns. From reading posts on this site, i've had pretty good luck with the electronics, at least until now.

OK, so the truck has been sitting in the garage, and I hadn't even started it for a month. Go out to start it and the battery is dead, not even a click. I have replaced the battery once since the truck was new, so this one is probably around 4 years old, has been sitting for a month, I have no suprise that it might be dead. I have a 12V 5A trickle charger which is meant for motorcycles, ATV's, and outboard batteries, the kind without a meter on it. It will charge a car / truck battery just the same, but you don't get any reading from it. So, I disconnect the ground cable from the negative terminal of the battery, connect the trickle charger and plug it in. The next day, I disconnect the charger and take a voltage reading at the battery terminals with a Digital Multi Meter, 13.1 volts. So I go to reconnect the ground cable to the battery and as they touch they give a fireworks show. Everything in the truck is off and closed, and the keys are not even in it. I thought, there shouldn't be any load on it, certainly not the kind of load that would create that kind of arcing and sparking. Thought about it some more and still couldn't think of any way there should be a load, so I thought maybe the cable and terminal just hadn't made a good connection and I should try it again but touch them together intently and firmly. When I tried that, with in a second or so, the battery terminal turned into a puddle in the battery tray, the cable started to glow orange at the connection and the insulation was smoking, and then a small flame burst where the connection was made. All in about a second flat, before I could jerk the cable away and blow out the flame. With in that second of time that the battery was connected and all that was happening, I did notice that I thought I could hear a motor or pump running which sounded like it was coming from somewhere down low in the engine compartment. I'm sure I heard that, but with the truck trying to start fire, I couldn't determine anything more about what it might have been. I did a visual check of all of the fuses and they all looked good. Again, the keys were not in the truck, and the only load I think there should have been is the under hood light. What the hell is going on here?

skeeter5

JDH, The only thing that I can offer is the alternator may have a shorted diode. This would be a direct ground. You can remove the large wire to the alternator and see if this removes the load. From your account, it sounds like the hot battery cable is touching the truck body, lots of amps (sparks) when you connect the battery ground wire.

Here is a site that has lots of good stuff, not answers but diagrams and manuals.

GM UPFITTER - Body Builder Manuals

I hope this helps, and good luck.