Automotive fuses
A fuse looks intact. Should you trust your eyes?
What this lesson covers
CORE TEACHING Fuse purpose; ratings; blade/maxi/fusible links; overload vs short; visual inspection limits; checking both test points. PRACTICAL DEMONSTRATIONS AND TESTS Voltage on both fuse tabs; resistance only when removed/de-energised; intentionally blown fuse comparison. ADVANCED / SCAN TOOL LAYER Scan codes can identify which modules disappeared after a supply fuse failure. KEY DIAGNOSTIC QUESTIONS Is power arriving at the fuse? Passing through it? What does the fuse actually supply? MUST-COVER CHECKPOINTS Identify feed side/load side; test to ground vs across fuse; loaded voltage drop; fuse rating; downstream loads; root cause of blown fuse.
What you will be able to do
A fuse looks intact. Should you trust your eyes?
Where it sits in the programme
- Builds on
- Lesson 11: Battery-going-flat diagnosis
- Feeds into
- Lesson 13: Voltage drop across fuses and finding active circuits