Electrical system maintenance helps prolong the life of fleet vehicles' batteries and circuits. Battery charging equipment maintenance helps connect, recharge, and jump-start vehicle batteries. Accessories support and extend the life of the batteries. Wiring and cable replacements maintain electrical components in a vehicle. Circuits, harnesses and relays may be removed and replaced to repair electrical issues. Vehicle starters help turn on engines when the battery won't function. Switches and spark plugs control the flow of current through vehicle electrical systems. Circuit testers check current flow to verify proper operation or identify wiring problems