Atanas Dimitrov

ok here is a good one. I am a diesel mechanic from a diesel shop. working on 08 GMC sierra 2500HD. stock. a tree fell on cab and a cab from a 1500 was installed 4 years ago. about 3 years this issue came. NCNS. the truck been at 2 other shops and at our for about 6 months. i have narrowed it down to the Can Hi wire. i keep burning modules first it was the ITBMC then truck started and ran for 2 weeks. and all sudden it dies same issue. then the TCCM was burned put new one. same thing. now i have no comm to ECM and and im stuck at 120OHMS. i believe the issue is under dash but cannot find it. when i perform wiggle test on can HI Lo wires from TCCM and DLC i jump from 120 to 450OHMS. any help would be great. I do know little on Can bus and how it operates. i do have TECH2 as well.