Hey guys, wondering if anyone could tell me how to test my clutch fan to see if it working properly. when towing I have high temps up to 215 - 220 even if Im not in the pedal. New thermostat didn't help and rad is clean. My trailer is about 9500lbs I pulled it in the mountains last year with no issue. Any input would be greatly appreciated.

 

The fan clutch should engage when the air conditioning is turned on. You can also check your trouble codes for the insufficient fan speed code.

 

Another way is, with the truck at operating temp, ground pin 1 on connector bottom of shroud. rev to 2000rpms you should hear the fan start to roar within a min or 2. This will set a code DTC 0480.