OER Parts offers a wide selection of Battery Accessories for your 2003 GMC Sierra 1500 HD. OER Parts offers 2003 GMC Sierra 1500 HD Battery Tender, 2003 GMC Sierra 1500 HD Battery Managment System, 2003 GMC Sierra 1500 HD Dual Battery System Controller Set, and 2003 GMC Sierra 1500 HD Battery Relocation Set. Battery Mat Battery Topper Battery Terminal Protectors Battery Post Cleaning Brush Battery Terminal Puller