a fan control module is provided for a system unit . the fan control module includes power outputs for supplying power to a plurality of fan . it also includes a temperature sensor for giving a temperature signal . it further includes a control unit connected to receive the temperature signal and including preprogrammed control information for determining power signals to be supplied to each of the fan units for controlling the speed thereof . the fan control module can control the fan units in a coordinated manner enabling reliable and effective cooling of the system unit under widely varying parameters . it can mean that existing system components can be employed in harsher temperature environments that they were originally designed for , without needed a complete redesign thereof . the fan control module can be provided with electrical noise isolation circuitry to isolate other components from electrical noise generated by the fan units . the system unit can , for example , be a computer system unit for rack mounting in a telecommunications application .