Learn how wire gauge, conductor length, temperature, insulation, identification markings, harness routing and connections influence a vehicle circuit. Explore a working teaching model and investigate wiring faults using electrical evidence.
Choose a lesson and mark it learned after reading. All progress stays in this browser.
Change wire gauge, one-way run length, temperature, load resistance and source voltage. This simple model includes both supply and return conductors and calculates their resistance and voltage drop.
Model limits: Uniform copper wire, equal-length feed and return, steady resistive load, ideal source and no contact resistance. This is a voltage-drop learning tool, not a wire-ampacity, fuse-selection, fire-risk, or OEM repair approval calculator. Higher current, bundled harnesses, insulation type and ambient temperature also affect safe wire selection.
Tap a numbered point in this generic harness. Select the component, then review circuit ID, color/tracer and connector cavity. Illustrative labels are not from a production vehicle.
A simplified 12 V, 6 Ω lamp circuit includes a feed, connector and ground. Select a fault, move the voltmeter probe (black lead at battery negative), and compare voltage readings with the symptom.
Simulation assumptions: Perfect wires except inserted faults; ideal 10 MΩ voltmeter approximated as non-loading; fuse displayed as open after short-circuit event without modeling its real time/current curve. Always inspect a short before replacing the fuse. Do not bypass protection on a real vehicle.
Answer all eight questions. Score at least 7/8 to pass; retry after reviewing the explanations.