Hey guys I have a 91 pickup 4x4 with the 3.0 V6 and i am having a really interesting problem. I have been having a very slow amp pull off my battery, it finally went dead a few weeks ago so i put it on the battery charger over night and let it charge full. Well when i get back out there the next morning i turn the key over and i have power to absolutely nothing. No headlights, no radio (which is independent of the ignition switch), no starter... nothing anywhere. Well i checked the battery and i have a full charge (12.7 V), i check ground and pull 12.7 again from the positive post to the frame, i check the starter and i have power from the positive lead to the frame there. I check the fuse boxes all the fuses are intact but i have no power at any of them. I checked the 80amp fusible link (which i read was a pretty common problem) i have no power at it but i am getting a good reading with ohms so i am assuming its still good. I am kinda out of ideas, ive been trying to follow the leads back from the starter to see what i can check next as far as power but ive gotten myself very confused, and looking at a wiring diagram seemed to make that worse. Has anyone got any ideas on where to go next?

 

You should always have power at the fusible link. How exactly did you test it?

 

There are two wires/cables from your battery - the heavy one that goes to the starter, and a lighter gauge one that powers pretty much everything else (including the starter relay, so the starter won't work if the smaller wire doesn't have voltage.) It sounds like your heavy cable to the starter is good, but that you might have a broken/corroded connection to the smaller lead at the battery. These can be subtle - it could be mostly corroded off inside the insulation but touch just enough to work for months, and then when you put the alligator clips from the charger on the battery you bump it and break the connection and everything is dead.

I would suggest careful inspection of the small cable and its connections at the + terminal of the battery.