Detroit optimised idle not functioning

OK I have searched high and low on Google and you tube and everywhere I can think of about this even pdf detroit manuals but I have a 2013 cascadia 13 speed manual and the 455hp DDEC15 I believe might be DDEC13 but I can't get this system to work nor find good instructions on how it works, truck has no check engine lights or codes, but will not idle shutdown, when I run through the procedure to activate the system stamped to the dash the idle management lamp that is supposed to come on does not and the truck idles continuously through the night. I bought this truck used from my company due to price vs the lease program and trucks offered, it was well equipped and taken care of for an old company truck so I decided eh why not it's cheap and easy, has a good trans setup, an engine im familiar with, and I can have it paid off in one year. I know it is temp related but I can't find concrete cut off Temps currently it's 45 F so I tried setting it up so the heat will kick on and off as needed and engine will stay warm buthe I can't get it to function.

 

yep found the issue idle shutdown was Disabled in the Computer by a previous tech with a diagnostic computer. why i dont know but the system functions perfectly now it idles when i need it to and shuts down and restarts when its set to.