Testing should include

inspecting, testing, and replacing the oil temperature and pressure switches and sensors
checking the operation of the parking brake indicator light system
checking the operation of the brake stop light system and adjusting and servicing as needed
diagnosing intermittent, high, low, or no gauge readings
testing the gauge circuit voltage regulators (limiters) and replacing as needed
inspecting and testing gauges and gauge-sending units and replacing as needed
inspecting and testing connectors, wires, and printed circuit boards of gauge circuits and repairing or replacing as needed
diagnosing the incorrect operation of warning devices and other driver information systems
diagnosing intermittent, high, low, or no readings on electronic instrument clusters
inspecting and testing sensors, sending units, connectors, wires of electronic instrument circuits, and repairing or replacing as needed.

ASE 2: V. Electrical/Electronic Systems: F. Instrument Cluster and Driver Information System (P-2)

Process/Skill Questions:

How would a balancing-coil gauge system be described?
How would a gauge sending unit be tested?
What is the purpose of the instrument voltage regulator (IVR)?
What is the importance of a stop engine light (SEL) and a flashing amber warning light?