Volvo 850 Heater system

A fan that only works on the highest setting or a cabin that won't get warm are classic signs of a worn heater unit in the Volvo 850. This group includes the fan motor, ballast resistor and expansion valve – components that control air flow and temperature in the cabin. If you have an OE number such as 9134932 or 9137937 noted down, you can most easily match the right part to your car. Always check the model year and version before replacement.