Freightliner wont start

Alright so the truck wont start...i turn the key and nothing...you just hear a like clinking sound in the front...and the gauge for the battery is all the way at the bottom in red...but theres no icons on the dashboard...I cleaned the battery terminals...checked everything in the front like oil collant etc just to make sure it wasn't the cause...so i try to start the tractor again...and everytime (this is the 3rd time its happened) i try to start it...ill sit there for like 20-30 mins doing that and then it'll start...and no the tractor doesnt turn off on me...only when i turn it off...it wont come back on for the time frame i just mentioned...does anyone have any ideas what the cause could be???

 

Loose ground location where you think?

 

That was one of my guesses...where is that located?

 

14 freightliner cascadia...and its everytime it turns off...and even the stereo wont turn on...it has no power...i bought another stereo to see if maybe the old stereo just burned out..but when i installed new one...wouldnt turn on at all...

 

Ok so I opened up the fuse box under the glove compartment...and started messing with the fuses and putting ones in and replacing some with new fuses...so i wait and turn the tractor on...sure enough it turns on...so i do that lile 5 times...the tractor turns on...i do that again...and the tractor wont turn on...so i saw a vid on utube this guy pushes repeatedly on the clutch...so i do that...the first time it doesnt turn on...i do that a 2nd time and sure enough it turns on...in the vid the dude was saying it could be a clutch switch...but then again thats his perspective for his tractor...im hoping maybe that is my problem??? lol