Shen Tong Car Voltage Auto TesterA.Connect the clips to chassis or to any groundB.To find live wires - probe wire & if it is live,the light in the handle will glowC.To find broken wires - probe along wre until the tester does not light D.To test fuses - touch the tip of the tesrter to terminal after fuse.If tester glows,then fuse is goodE.To test light sockets ( brake lights,back up light,etc ) - touch aligator clip to chassis or ground and then probe to the tongue at the base of the shell10 Unit Voltage Tester :1.3A2.5A3.7.5A4.10A5.15A6.20A7.25A8.30A9.35A10.40A..