All power lost at crank

[saf_blu302]

On my 95 gt, I've replaced my starter, brand new battery(*13.1v and has passed a crank apms test*), ignition switch replaced, tested every fuse and relay, all fine. My ignition, (*sometimes*) will allow all my lights on at the on position, but when I crank it, there's a slight tick then I lose all power. The s pin gets disconnected from the ignition, I don't lose power but starter doesn't engage. Any idea, I think bad ground but idk where they are or how to fix it.

 

[General karthief]

Start at the battery cables and check, clean and tighten both cables. And follow them one at a time clean and tighten, you have a loose or bad connection. Start at the battery.

 

[AeroCoupe]

Would also suggest doing some voltage drop testing.

 

[86HO5.0]

Would also suggest doing some voltage drop testing.

An often overlooked diagnostic. Many people check voltage at rest and call it a wrap.

 

[General karthief]

^^^^this is very true, I speak from experience when dealing with a 'no crank' situation, click and power goes away more times than not it a loose/dirty cable connection at the battery..the voltage drop test starts (generally) at the battery anyway.