GMC Repair: 2008 Sierra Denali dead but battery is o.k., 2008 sierra denali, pi number

Question
We have a 2008 Sierra Denali and the battery is 3 months old.  The volts sometimes go up and down intermittently while driving and sometimes almost shuts off.  It will be fine and then it is dead.  Nothing works.  If we wait a few minutes it will sometime turn back on but sometimes it won't for days.  We have had it towed to the dealer 3 times now (even when dead) and they haven't been able to find anything.  The cables are showing charge in and out and the battery is good.  It seems like there may be a short somewhere that completes itself sometimes and sometimes it won't.  We have talked to others that have had the same problem and never been able to find the solution.  It is at a dealer now, it was dead when it arrived, they checked it out and couldn't find anything.  It started the next day and has been fine ever since.  Any idea?????  Thanks!

Answer
Hi
There are several service Bulletin out to address different sources of power loss on this years vehicle.
Here are the bulletin numbers.
You can Search them, and be able to pull them off the internet with pictures to assist in diagnosis.

Bulletin or PI number


Description


08-06-03-008.


Information on Intermittent Battery Drain Diagnostic Tips and Recommendations


PIT4613A


Check Mega Fuse


PIT4050E


Ckts (6815 or 6817) Shorted or the ISLPS/IS Lamps fuse may blow


PIT4816


Multiple Electrical Concerns With DTC C0900


PIT3385E


Roof Beacon Switch Left On Causing Battery Draw


07-06-03-002B


Information on Inspecting Top Post Battery Cable Bolts, Clamps and Nuts During Pre Delivery Inspection


PIT4412A


Vehicle Will Not Crank / Start At Times / Aftermarket theft relay


06-08-45-009A


Multiple Electrical Concerns due to wiring in B pillar


06-08-44-032B


Rear DVD Screen Blank, Inoperative, Speaker Pop Noise, Battery DrawNav Screen Flashing,
 Hope this helps