To perform a voltage test, turn the engine OFF and turn the headlights ON and leave them running for 15-20 seconds to discharge any surface charge from the battery and then use a DVOM set to Volts DC to probe across the battery terminals and note the voltage reading. For no load test, we should connect a tachometer to engine and it should be in PARK position of Transmission and we should set the emergency brake and switch off all the electrical loads and start an engine and increase speed to around 1500 rpm and check the voltage of battery, it will show an increase of at least 0.5 volts but no more than 2.5 volts. If the voltage doesn't go up by more than 0.5 volts, the alternator is not charging and if it goes to further than 2.5 volts it is overcharging, usually because there is something wrong with the alternator or any other component and further testing is required to see what exactly broke. For a load test, with the engine running, turn on the blower motor and high beams, increase engine speed to 2000 rpm and measure the voltage at the battery, which should be increasing at least 0.5 volts from the previous test, where a failure to meet specifications indicates a malfunctioning charging system. In the process of removing and installing the alternator, disconnect the negative cable of the battery, loosen the adjusting bolts of the alternator if equipped, remove the drive belt, disconnect the electrical leads, remove the mounting bolts of the alternator, and the alternator can be removed. For installation, make sure to place the alternator into the bracket, make sure to secure the mounting bolts, connect the electrical leads, install the drive belt, tension, re-connect the negative battery cable, and check whether the alternator is working. Specific models such as 850/C70/S70/V70 will require the power steering pump and tensioner bracket be removed to get to the alternator and then you will follow similar steps as outlined for the installation.