An automotive vehicle electrical system tester is provided for testing an electrical system having wiring which couple a load to a battery. The automotive vehicle electrical system tester is configured to measure an electrical parameter of the wiring and includes a first battery terminal connection configured to couple to a first terminal of the battery. A test connection is configured to couple to a wire of the electrical system which extends between the first terminal of the battery and the load. Test circuitry coupled to the first battery terminal connection and the test connection is configured to draw current from the battery along a path through the wire and to the test connection. The test circuitry measures an electrical parameter of the wire.