[tonye]

The other day the new battery on my S-10 pick went dead. I charged it and when I went to connect the +/- leads it didn't only spark it arced leaving burn marks on the terminal. Now the ECMD 10 amp fuse blows... what the heck just happened! The wires look good to the alternator and starter also checked for grounds and continuity... everything looks good! Could a new battery have a short?

 

[oldeerslayer]

Is this on your 1951/1991 S10?
What kind of wiring harness are you running. One from a custom wiring outfit or did you build the whole harness yourself? I couldn't find an ecm D fuse on any stock S10 wiring diagrams.

 

[tonye]

Far left bottom open 10A fuse keeps bowing.

 

[oldeerslayer]

That's what I kind of thought, it's ECM B. Been doing this a long time and never saw a "D" fuse.
That's really not important. What is - is what are you running for an engine harness? Sounds like something has a major short to ground.

 

[tonye]

Thanks for the info my friend... I just got back with a new battery and will install it and let you know it the old battery had a bad cell. The wiring harness is not OEM by any means, it was put together by the original owner in California.

 

[tonye]

The battery was definitely bad... but it did fix the problem! I cranked the engine but it didn't start but as soon as I connected the wires to the alternator the ECMB fuse popped. Check the positive wire including the wire that goes to the alterator for a ground and it was good. These two wires connected together from the alterator are grounding to the frame. They to go into a makeshift harness that goes buried into back.

 

[tonye]

anyone have an idea where they go to! ¯\(ツ)/¯

 

[oldeerslayer]

Think you're going to have to remove the loom and follow them.

 

[tonye]

Think you're going to have to remove the loom and follow them.

yep, that's the plan my friend!

 

[Lonnie P]

Those 2 are are NOT grounds. Grounds will never be fused & that is the power terminal at the alternator
The fusible links in them clearly define them as power carrying conductors.

Those are the 2 main power feeds for the harness.

If you ohm them out, you may get continuity to ground because of the devices various connected to them, but it should read some resistance, not 0 ohms, which typically defines a short.

A battery with a short usually means it is dead as it expends it's energy internally.
A spark when connecting it has nothing to do with the battery. That is the result of a short in the wiring.
Your blown fuse proved that.

 

[tonye]

Those 2 are are NOT grounds. Grounds will never be fused & that is the power terminal at the alternator
The fusible links in them clearly define them as power carrying conductors.

Those are the 2 main power feeds for the harness.

If you ohm them out, you may get continuity to ground because of the devices various connected to them, but it should read some resistance, not 0 ohms, which typically defines a short.

A battery with a short usually means it is dead as it expends it's energy internally.
A spark when connecting it has nothing to do with the battery. That is the result of a short in the wiring.
Your blown fuse proved that.

Thanks Lonnie! (¬‿¬)