hello, so ill try and keep it short, i have a 2009 5.3/6l80e all works perfect. I had to replace the computer to get an OS from a 2500/3500 so my BCM will enable high idle option. Apparently the 1500 ecm wont do it. I got a 2010 savannah van 3500 ecm it was a 6.0, i put it in after doing vats delete. it started and ran like crap, it high idled on cold start up like it supposed to when trying to idle down it went to shit. thinking maybe the van had VVT i checked it and DOD, my motor has DOD but its disabled and not wired in. turned them off and it still did same thing. I then copied all the differencs from my 2009 5.3 ecu to the 2010 6.0 ecu and it starts and runs fine now. My BCM high idle switch works like its supposed to. However, now my fan 1 comes on after about 45-60sec. mind you motor is dead cold. I have checked the file several times and compared to my 5.3 tune, everything is identical! Why would the fans be coming on so soon. Is it possible the ECM needs to be pinned different for van to 1500 truck? Im not inclined to think its wiring because they dont turn on right away its always a delay, and they do turn on, so its some control issue im missing. I have attached my working 2009 5.3 file and the 2010 6.0 file. thanks in advance