Use the instrument cluster in a truck by looking at it while the vehicle's engine is on. The instrument cluster displays critical information about the vehicle, including RPM speed of the engine, temperature, oil pressure, battery charge level and speed while driving. Different model trucks may display other information relevant to specific pieces of equipment on the truck, such as the status of a four-wheel drive mechanism if one is equipped.
An instrument cluster typically only gives useful information while the engine of the vehicle is turned on. Some clusters may display limited information if the vehicle's key is inserted. This information may include the oil pressure and battery charge level. Analog instrument clusters are still in use in some vehicles, but digital instrument clusters are rapidly taking over as the primary type in new vehicles as of 2015. Digital instrument clusters generally show completely blank screens when vehicles are turned off, as they require power to function.
Understanding vehicle instrument clusters is important due to the critical information they display. Problems with a vehicle are often displayed in the form of a warning or error light on the cluster. If the instrument cluster in a vehicle stops working properly, it should be fixed immediately.