Went out to start truck and have a dead short to positve batt. cables. Just recently did rear drum brakes and just put two new batteries in truck, Other batts. were old and run down by leaving glove box open all the time I was working on brakes. Any ideas where to look or how to start, have a little meter. Seems coincidental I just put in new batterys but i dont know what I could have done to cause a short. Help? Thanks . Byron

 

Do you have all you lights and radio heater etc.? It won't crank at all?

 

A dead short???? Find where you pinched wires during your repairs.
A dead short would indicate smoke ect. You can see where it shorted!!!

 

I should have been clearer, Had no power at all batts. completly dead no dome light , no dash. The dead short was I read the resistance between the positive batt.cable to ground and it was zero. Put batt. on charger, verified it was dead. Just finished pulling the fuses and relays to see if the short would go away. The only one that made a difference was the 140 amp alternator fuse. With that one pulled I no longer read zero between positive batt. cable and ground. My question is Now , With the truck off should I be reading an open across the alternator. Im thinking my alt is shorted out. The truck is a 98 with 170k miles. Doesnt pulling that fuse for the alt. removing the short between cable and ground prove the short in the alt.?? Thanks Byron.

 

I Would say It proves its in that line...maybe ires to alt are chaffed and arcing ect. check all visible wires from alt then if nothing found get alt checked out.

 

Take the positive lead off alternator terminal. If you still have short, it's in wiring. Otherwise continue taking alt off for futher testing of alt at parts store.

 

took off the alt. wires, still have a short, also the two wires from the alt. show no resistance between each other. There is a kind of resistor or something built into the wires where they connect to the alt. Anyone know what that is? The large wire going into it has a split in the insulation and bare copper is showing. Im lost, guess its garage time. Have the weekend to mess with it somemore, cant take it in till Monday. Thanks for the tips, Byron.

 

One member had a dead short in his alt supply wire. It,s a number 4 gauge wire I believe, the same gauge as some battery cables with lugs on them. Just piggy back a new cable from the alternator across the front of the engine.

 

are you sure one of the new batteries didnt take a dump?

 

The two small wires should not have continunity to each other, or will either have continunity to the large wire you removed from alt. Sounds like you have contunity from large wire to radiator or somewhere in that area.

 

How fast did it go dead?