On car starter test

Battery test

check that the battery is charged and that it is working properly by testing its volts or test it using a hydrometer

then disconnect the fuel system or ignition system by unplugging the fuel pump or the distributor.

Crank the engine while the multimeter is connected. The voltage should not drop under 9.5 volts

Voltage drop test

Use the multimeter to determine the voltage drop between the negative terminal of the battery and the starter motor's body. Then check the voltage drop between the battery's positive terminal and the starter's terminals