2005 Chevy Silverado 2500 HD brake system warning

[Tanner nolen]

So I bought this truck used, it is at 169,000 miles now. It had always shown a warning once in a while “service brake system”. It only comes on periodically while driving. Also ABS light is on always, as well as the “service airbag” light and warning over odo display. I have check all fluid levels including the power steering, removed and cleaned all ground pieces to frame, and am not sure where to go from here. Any direction would be much appreciated. Thanks in advance! I should also add that there are no codes being thrown, only the warnings displayed in the dash

 

Edited March 30, 2020 by Tanner nolen
Information needed to add

[riverbanks]

Probably should start with a proper scanning,mostly guessing otherwise