THERMO Control Fan: Testing

In cases of engine overheating or insufficient air conditioning, proceed as follows:

1. Start with a cool engine to ensure complete fan clutch disengagement. Cover radiator grille sufficiently to induce high engine temperature.
2. Start engine and operate at 2000 RPM and turn on air conditioning, if equipped. A fan roar will be noticed when fan clutch engages. It will take 5-10 minutes for fan to become engaged. While operating engine under these conditions, observe temperature light to prevent overheating. If hot light comes on, remove cover from radiator grille.
3. As soon as clutch engages, remove radiator grille cover and turn air conditioning off to assist in engine cooling. After several minutes fan clutch should disengage. This can be determined by a reduction in fan speed and roar. If fan fails to function as described, it should be replaced.
   Fig 1: Thermal Control Fan Drive Unit

   
   NOTE: Rotation speed will vary with engine temperature.