Service Electrical Cleaning or Replacing Battery c CAUTION: Avoid injury! Battery gas can explode: · Keep sparks and flames away from batteries. Use a flashlight to check battery electrolyte level. · Never check battery charge by placing a metal object across the posts. Use a voltmeter or hydrometer. · Always remove grounded (-) battery clamp first and replace it last. 1. STOP engine. 2. Remove grille. 91