Fault-finding practice
Knowing what a relay does and being able to find the one that's broken are different skills. A question bank only ever tests the first.
These give you a symptom and a circuit. You choose where to probe, you get a real reading, and you call the fault when you're sure. You're scored on how few probes it took — because working a circuit efficiently is the actual job.
Marker lights dead down one side
The driver-side marker lights are out. Bulbs are good, the fuse is good, and the passenger side works fine.
Builds on: Voltage drop Core skillSlow crank on a warm engine
The engine cranks slowly and unevenly. The battery has been tested good and is fully charged, and the starter has already been replaced once.
Builds on: Starter circuit Puts it togetherRelay-controlled pump won't run
The pump does not run and the relay does not click. The pump motor itself has been bench-tested good, and its fuse is intact.
Builds on: Relays