A heat dissipation device has a main controller and a fan module having a motor coil, a connection interface, a PWM driving circuit and a fan monitor chip. The connection interface has a control pin, an error report pin, a power supply pin and a ground pin. The control pin receiving a control signal. The PWM driving circuit adjusts current magnitude and current direction of the motor coil to drive the fan module. The fan monitor chip is connected to the connection interface and the PWM driving circuit, receives the control signal, generates and sends PWM signals to the PWM driving circuit according to the control signal and sends an acknowledgement signal via the control pin after receiving the control signal. The main controller can check if the control signal is correctly received based on the acknowledge signal.