5.After the wires were hooked up, the fuse was installed and the fans were unplugged. Then, the truck was started and warmed up to the desired "Low" temperature setting. Next, the technician pressed and held the "Low" button on the FAN-PWM module and waited until the light began to flash. The process was repeated to program the "High" setting. Generally, the "Low" setting is at or around 170 degrees F, and the "High" setting lies between 205 and 210 degrees F (15 degrees above thermostat).