hello everyone, my 93 silverado 3500 dually was running fine not too long ago, but recently i replaced the starter, alternator, battery, and thermostat, but that doesnt seem to be the problem, but i was hauling my camper, and about 40 miles from home it started overheating so i headed back home, it had no power and seemed like the trans was slipping in and out of gear, and then just died, had to get a semi wrecker to pull me home and was trying to figure it out, no blown fuses, and has power to the starter but it wont crank and it wont even give power to lights or window motors with the key on or off, i recently had it in the shop for a general inspection, and everything was fine in the electrical system, but cant figure it out now, it seems to be a short somewhere but its not draining the battery or anything, even tested the battery with a dvom, and it was at 12.6 volts which means its fully charged, but any help with this problem would be greatly appreciated, thank you.

p.s. also the camper is a fifth wheel and i had to get the connections for the trailer brakes and like put in at the place i bought the camper, but all they did was put a relay and wire between the battery and the connections to the trailer plug in.

 

you might be on track, with an electrical short. sounds like a fusible link / relay may have failed causing loss of battery supply to a few individual circuits, like the engine cooling fan for one. windows, lights ect. Probably would help if can obtain a factory electrical schedmatic.