2020 Peterbilt 579

Switches are not working on a 2020 Peterbilt 579, dash lights come on for the option but don’t function! the PTO is also on that bank but it stays on and does not disengage! pto light stays on no matter what and yes does stay engaged! Diff locks/fifth wheel slide/air suspension I took the plug off the bank where solenoids are the 6pin and there’s power (one pin is 11V the other 2 on same side have dashes and light is dim, the other side has nothing. I took all the connections off one by one of the cab module guessing the wires don’t go there (located under driver side cab, not sure what else to check. Although coworker replaced a chassis fuse soon as he did, air to PTO happened but fuse tested good so maybe a fluke it happened like that?

 

But isn’t each solenoid for those different options how could they all go bad at the same time? Not sure how that bank works like if first one messes up then the rest don’t?

bQUOTE="Claytonbigsby, post: 13109837, member: 247009"]Those solenoid banks are common to go bad, recently had a w990 with your same issues. I ended up taking a bank assembly from different truck to test before I replaced the solenoid bank on frame and everything worked normally again.
The module that holds the solenoids was about $180 and individual solenoids (if you choose to replace those too) were $60ish each from KW dealer. The module doesn’t need to be programmed, it will work out of the box.
The solenoids can be swapped around- there’s nothing special about a diff lock solenoid vs the 5th wheel slider one when they are disassembled.[/QUOTE]