Final answer:
Indicator lamps provide vital information to drivers about their vehicle's systems, including fuel level and engine temperature, using voltmeters connected to sender units.
Step-by-step explanation:
Indicator lamps provide the vehicle operator with information regarding the operation of main vehicle systems, such as battery charge level, oil pressure level, and airbag system status. These are often represented on the dashboard by various gauges and warning lights. For example, fuel and temperature gauges in a vehicle, like a 1996 Volkswagen, use voltmeters that register the voltage output of 'sender' units, reflecting the amount of gasoline in the tank and the engine temperature. It's also common to see lights dim in the vehicle, like the passenger compartment light, when you start the engine of your car, which can be an indication of resistance inside the battery itself.