The VOLT portfolio of components includes a range of heater blower motor resistors, fan speed controllers and radiator cooling fan pre-resistors. The range has been developed in response to customer demand for a full range from a single supplier with comprehensive application data.
The range encompasses all original equipment resistor types into one range including traditional resistor based components and modern electronic speed controllers for both blower motors and radiator cooling fans. It includes 138 part numbers covering 170,000 applications that cater for over 4.6 million cars on the road.
A supporting range of repair kits is also available for key applications where the wiring loom/connector is often damaged by overheating.
Only Original Equipment thermal fuses are used in the manufacture of VOLT resistors ensuring safe, reliable operation.
Heater (Blower Motor) Resistors
The heater resistor is also known as the heater blower motor resistor because it fundamentally controls the fan speed of the interior heater.
The VOLT range covers both traditional resistor based controllers (which typically feature 4 speed settings) and modern electronic speed controllers used in vehicles with more advanced automatic climate control systems.
The heater blower is one of the most commonly used cabin functions and so it is no surprise that these components are prone to wearing out. A failed resistor can result in several outcomes. The fan may stick at one speed (the variable control is lost), the fan may fail to work on some settings but continue to operate on others, or there may be no fan function at all.
Pre-Resistors (Radiator Fan Resistors)
The pre-resistor controls the speed of the radiator/cooling fan. Using information from the coolant temperature sensor, the vehicle activates the cooling fan when needed. Power to the fan is routed through a pre-resistor, which allows the vehicle to control the speed of the fan depending on the temperature of the engine. An increase or decrease in resistance effects the voltage though the motor, resulting in the required changes to fan speed.
Like any component, pre-resistors can wear out over time. A faulty or failing pre-resistor can result in the cooling/radiator fan failing to work, getting stuck at one speed or refusing to turn off (sometimes even after the car is turned off causing battery drain). Often the first sign noticed by the driver is an overheating engine.