2009gmc1500

[tommyDean]

Helptruck wont turn over whenturning key to start dash goes black itsays engine laking power

[Doug_Scott]

Clean battery connections by loosening and removing them.  Clean both cables and battery posts.  Put cables back on and tighten.  Remember to remove negative first, and to put positive back on first. 

You may need to boost battery if 8t is dead.  From your description it is either a bad connection on battery or dead battery.  Take a look at the ends of the ground cable.  Look for a split in the plastic around the cable at the engine end for any corrosion in there.