No CRANK after rain.......

[Wes Harden]

what that means is 12.77 volts found it easier to go through your meter to ground, than the main ground cable. that is bad news. means high resistance on the ground circuit.

If you had seen .5 volts or less that would prove a good ground circuit. works on positive side too.
Is called a voltage drop test.
electricity is like water, it wants to find the easiest path back to it's neutral level.

 

[Wes Harden]

Also I am pretty anal retentive when it comes to battery connections. Most people over tighten top post style clamps. The lead clamps will be ruined by over tightening.

seeing no gap at the clamp split and post below clamp level tells me it is not installed properly. I always expand the clamps, wire brush clamp and post, install, tighten with short wrench by hand. I will attempt to twist the clamp if I can it is not tight, if I can't it good. If the ears of the clamp split are bending in together it's over tight. The clamp should never close completely. If the clamp split closes the post is to small.
Don't care for the felt "battery saver" washers the parts stores sell. I never use and have little to no corrosion issues. If a battery has a crack in the case and corrodes the cables, a new battery is obvious, but cables may not be savable. The cable may still corrode.

 

[Blue85]

Start with the basics for no crank and pull off the battery terminals...

Assuming you have checked and cleaned the power and ground leads from the battery as stated before...

Probably when you swapped the battery you messed with the negative enough to get better contact, but it was never installed right, giving you the classic bad connection symptoms (everything seems to have power until you turn to "start").

I like how the chart refers to the green eye.