Bad electrical short issue

[learfxr]

I took a huge gamble on a used 2003 Ranger 3.0 5spd that won't run. The lady said she drove it to Walmart and then it wouldn't start again. She said they replaced the alternator and starter previously. I drug it home tonight and just took a quick look at it. They had the battery disconnected so I checked voltage on the batter, 5 volts. Put a charger on the battery while I started wandering around the truck looking at things for a few minutes. I decided to put the positive cable on the battery and it arced a lot. I checked resistance from the positive battery cable fitting to a ground bolt on the inner fender and got indication of a direct short.

Is there a common area that these trucks may short against the metal? I can't check much tonight since it's still on the trailer and it's late outside. I'll start going through everything tomorrow.

This poor truck was driven down a dirt road for several years and it's packed with mud everywhere. It's had a rough life, so I'm going to clean it up and try to get it running and driving again.

Thanks for any tips you can provide for locating a short

 

[RonD]

No, no "common" short

You said positive cable shows 0 ohms to ground, dead short
There should be Two Positive cables, one to starter motor and smaller one to fuse box
Disconnect starter motors cable then retest for short
If it still shows 0 ohms to Ground then leave starter cable off and not touching metal, and give that cable a good look to make sure it isn't bare and touching metal

Open fuse box and pull out Fuse #1, 50amp, it powers cab fuse box, make sure positive battery cable is not touching metal
Do ohm test on each leg of Fuse #1, neither should show 0 ohms
If one does then test ohms between that leg and positive battery cable, if 0 ohms then that leg is the Power side of the fuse, and also connected to Alternator
Remove alternators 3 wire connector AND B+ wire on back of alternator, see if 0 ohms goes away, if so test B+ stud to Ground, if 0 ohms then alternator is bad
If it still shows 0 ohms with alternator disconnected then test each alternator wire for 0 ohms to Ground.
Alternator wires use Fusible Links, these are suppose to blow and NOT short out if amps get to high, but...............fusible links are closer to fuse box end on these wires so start unwrapping wiring harness at that end.

If all checks out then move to the other fuses in the engine fuse box, one leg on each fuse will be Power leg, connected to positive battery cable, if the other leg shows 0 ohms then it will be the short
Fuse #11 is another 50amp fuse and it powers the ignition switch, and like fuse #1 it has sub-fuses that can be tested as well, in cab fuse box

And battery is bad, 5volts means it self drained and won't hold a charge for any length of time.

 

[Curious Hound]

She said they replaced the alternator and starter previously

The connections on these 2 devices are where I would look first. A lug not positioned right or left loose so it could move around and touch ground is a very likely culprit. Always check what was messed with last.

 

[learfxr]

I removed the alternator wiring and it didn't help. I removed the starter and disconnected the wires and it was fixed. I ran to Oriellys and picked up another starter. It now runs and drives. It needs lots of work, but it's running again

Thanks for the advice guys.

 

[learfxr]

No, no "common" short

You said positive cable shows 0 ohms to ground, dead short
There should be Two Positive cables, one to starter motor and smaller one to fuse box
Disconnect starter motors cable then retest for short
If it still shows 0 ohms to Ground then leave starter cable off and not touching metal, and give that cable a good look to make sure it isn't bare and touching metal

Open fuse box and pull out Fuse #1, 50amp, it powers cab fuse box, make sure positive battery cable is not touching metal
Do ohm test on each leg of Fuse #1, neither should show 0 ohms
If one does then test ohms between that leg and positive battery cable, if 0 ohms then that leg is the Power side of the fuse, and also connected to Alternator
Remove alternators 3 wire connector AND B+ wire on back of alternator, see if 0 ohms goes away, if so test B+ stud to Ground, if 0 ohms then alternator is bad
If it still shows 0 ohms with alternator disconnected then test each alternator wire for 0 ohms to Ground.
Alternator wires use Fusible Links, these are suppose to blow and NOT short out if amps get to high, but...............fusible links are closer to fuse box end on these wires so start unwrapping wiring harness at that end.

If all checks out then move to the other fuses in the engine fuse box, one leg on each fuse will be Power leg, connected to positive battery cable, if the other leg shows 0 ohms then it will be the short
Fuse #11 is another 50amp fuse and it powers the ignition switch, and like fuse #1 it has sub-fuses that can be tested as well, in cab fuse box

And battery is bad, 5volts means it self drained and won't hold a charge for any length of time.

Thanks for the tips.

I put a charger on the battery and so far it has recovered. I'm sure it hurt the life of the battery being discharged the way it was. I have no idea how long the truck was parked after the issues. I've driven it around the block a few times and it's holding up so far

 

[Curious Hound]

Congratulations

Eric B

 

[Doofy]

Great job! Thanks for the update.

 

[RonD]

+1 Good Work