2007 Freightliner Century D60 no start

Hello, i’m having an issue with my 07 freightliner century D60. It started a couple of days ago, it would take a couple key turns to start the truck. I would turn the key and hear the one click sound and it wouldn’t start. I would have to turn the key 3-4 times until it would start. once it got started i wouldn’t have any issues while it’s running. but starting the truck got progressively harder. my only problem was getting it started. so i decided to clean all the battery cables connected to the battery and the grounds. still no start. and i also notice that my interior lights wouldn’t come on anymore after cleaning the ground to the chassis. when i tried to undo the bolt to chassis i snapped it off accidentally and had to screw in a new bolt. the old bolt was welded to the chassis. i’ve add pictures of the new bolt to this thread, please let me know if you see an issue with how i put this new bolt on. i then took the batteries to a local auto zone where they informed me that all the batteries had 100 percent charge and they didn’t show any issues. when i turn the key to the on position before cranking it my voltage meter shows around 12.5-7. I’m thinking it’s most likely the starter. but could it possibly be something else?
any help would be appreciative. Thank you. 007

 

Thank you, i’ll try that tomorrow, i went ahead and changed the starter and still have the same problem.

 

thank you! you were right. it was the ignition relay. put a new one in this morning and the truck fired up immediately.