Final answer:
A customer experiencing shocks from a vehicle should first have the vehicle's electrical system checked for leaks or faults by using a multimeter to identify any unintended current flow.
Step-by-step explanation:
If a customer complains of receiving shocks from his/her vehicle, the first test should be a check for electrical leaks or faults in the vehicle's electrical system. This involves testing the car's components to ensure that there is no unintended current flow which could cause shocks. It is important to assess the amount of current (I), the path taken by the current, the duration of the shock, and the frequency of the current (f), with frequency f being zero for DC currents. One way to test for potential leaks is to use a multimeter to identify points with the same potential that should not be conducting electricity. Since the severity of an electrical shock is determined by the current flow, as influenced by voltage and bodily resistance, it's crucial to identify the source and quantity of current causing the shocks.