To locate the source of the short circuit, first disconnect the load elements of the circuit (circuit load elements are elements that consume electrical current, such as light bulbs, electric motors, heating elements, etc.).
Remove the appropriate fuse and connect the tester or voltmeter leads to the fuse terminals.
Turn on the power in the circuit, while not forgetting that some circuits of electrical equipment are turned on only when the key in the ignition switch is turned to a certain position.
If voltage is present (as evidenced by a control light or voltmeter readings), this means that there is a short circuit in the circuit.
If there is no voltage during the test, but the fuse still blows when that circuit load is connected, this indicates a failure of the load element.