One power-distribution bus. Multiple branches. A shared voltage supply, separate grounds, relay control and an ECU sensor signal. Trace the system, choose your tests, and defend a fault diagnosis with evidence—not a guess.
Training model only. It uses simplified resistive loads and an ideal regulated 5 V sensor reference; it is not a vehicle-specific schematic or an exact model of relay timing, fuse time-current behavior, ECU inputs or motor startup current. Refer to OEM information and appropriate safety procedures before working on any vehicle.
Trace/highlight:
Power / signalReturn pathSelected branchFault highlighted for learning (explore only)
12.60 VShared bus P0
2.10 AHeadlamp current
4.20 AFan current
2.50 VECU sensor signal
03 / Test before you conclude
Set the red and black leads independently, then measure. Voltage is reported as red lead potential − black lead potential, relative to the battery negative reference. Clickable diagram points set the red lead.
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Use the meter to collect evidence. The measurement history below records what you actually tested.
Measurement history
No measurements yet.
Field safety: Voltage-drop testing is performed with the circuit operating, when safe and authorized. Never perform resistance or continuity tests on energized circuits. A virtual test point is not permission to probe a real connector, SRS or high-voltage system.
04 / Diagram interpretation challenge
The branches share a B+ feed, but use different fuses, control devices and ground points. Select the correct diagram interpretation, then reveal the explanation.
A headlamp and fan both run slow while the sensor reference remains at 5 V. Which single measured location would most directly test their shared supply?
2 / PredictWrite down expected readings at each point under the stated operating condition.
3 / VerifyUse loaded voltage-drop and paired signal measurements to isolate the fault location.
05 / The Challenger's diagnostic missions
Mission 1 of 6
Each mission loads an unknown fault. Your job is to prove where the defect is using two mission-relevant tests before submitting a diagnosis. Fault selection is disabled during missions; explore mode is for practice.
Not started
Mission 1
Start the mission to load your vehicle complaint.
Evidence collected
0/2 required tests
06 / Final knowledge check
Answer at least 4 of 5 questions correctly to pass. Completion requires all 10 lessons, all 6 diagnostic missions and a passing assessment.
Not yet graded
AUTONATOMY • Electrical & Electronics Fundamentals • Wiring Diagrams, Harnesses & Connectors • Mini Course 08. This offline learning prototype saves progress in this browser only. It does not issue an accredited credential or replace supervised hands-on training.