Weird No Starter Juice After Battery Disconnect

96' 4x4 2.7
After changing the dreaded fuel filter while trying to trouble shoot a major bog in the motor, my son decides to disconnect the battery for the evening so it gets a 'restart' to the electrical, he did however leave the negative connected. He reconnected the positive side a few hours later and nothing but a click and some buzzing behind the dash. I checked the battery numerous times and used my start box and nothing, just a click or two. The headlights will take a minute to come to life as if they were on a dimmer ???? Any thoughts or suggestions, I do not beleive this is a starter issue, I tapped it a few times and nothing.... Battery is showing 75% with 12.5 volts

 

Check the main fuse and 80 amp battery fuse. Might of popped them put cable back on. Always disconnect negative first, install last. You don't want to know how I learned that..

 

Also all connections are tight and clean?

 

UPDATE ! and slightly embarrassed.... after checking every fuse and preparing for the worst, I had the kid turn the key and I gave the positive battery connector a good shaking... Started right up.... Just need to be taken apart and cleaned thoroughly.... now on to the engine bog.... thank u lucky13 for your responses...

 

All good. I drive for 3a. I deal with that all day..glad it was a easy fix