Grille shutter control device

A grille shutter control device comprising:

• a control section connected to a communication line in a vehicle, the control section controlling opening and closing of a grille shutter that introduces air to a cooling target of the vehicle, and controlling to open the grille shutter in a case in which a communications fault is detected;
• and
• a diagnostic section connected to the communication line, the diagnostic section detecting a degree of opening of the grille shutter by communicating with the control section, and, in a case in which the communications fault is detected, the diagnostic section diagnosing a malfunction of the grille shutter if a degree of opening of the grille shutter immediately preceding the communications fault is less than a pre-specified threshold value and a temperature detected by a temperature detection section is higher than a pre-specified threshold, the temperature detection section detecting a temperature of the cooling target.