this summer I went to start my truck in the morning and got nothing. Every light on dash on, cd's turning around, door locks going crazy. After work put charger on it and after a while it started as normal, no lights on dash. I went to auto zone to have battery checked out (their battery) everything ok. All summer I kept jump box in truck just in case. Fast forward to Nov 27 . I go to start truck , but before that I put in the range technology v4 disabler that I have been using and again all lights on dash come on but it starts this time. I didn't have the range when this happened in summer. Called dealer and he said it sounded like a battery problem with all the lights on dash going on. Again off to auto zone, this time after I restarted truck only check engine stayed on. Battery was checked out as good but I had a bunch of codes. Next week off to dealer (gm extend war) where they found that the neg battery cable was "355-ma out of specs". Service writer said one of the techs son had the same thing on a Tahoe he has and they think this was the fix, as it has not happened again. There is a post on here (believe the range tech. thread) where somebody had same problem as me and using the range. This person went to dealer but never came back to say what happened. I hope the range tech v4 disabler is not the problem because man with that thing in truck runs way better.