B4000 completely dead

[that_one_guy]

Went into the store for about 5 mins came back out and went to start it and it was dead. The radio wont turn on nothing. The door locks barely work. The dash volt meter doesnt even register. Had the battery tested has 12.9 volts. Is there like a master relay or a master fuse?

 

[that_one_guy]

this is a 94 by the way.

 

[srteach]

There is always a main fuse. If blown, it would cut ALL power to the whole truck. The battery could have 24 volts and still not be able to produce the amperage. Clean the battery cables, check amp draw on the starter. Does it start with a jump start?

The starting electric is only from the battery, but depends on the starter draw. If the battery cannot supply the amperage required by the starter, how can it provide the spark at the same time?