Radiator fan only turns on when the AC is on
I have a1997 Ford Thunderbird 190,000 miles and
she runs like a champ, but the radiator fan only
turns on when I turn on my AC. I have changed the
thermostat, and I have checked the engine coolant
sensor and the water temperature sender for
power and resistance, which they both seem to be
working properly, and yet the fan still will not turn
on. What else should I troubleshoot?
Check the "constant control relay module" (CCRM) it governs fan operation.
Oops, let me add: fan is controlled by BOTH the CCRM and the powertrain control module (PCM). From the manual: "The cooling fan motor is controlled during vehicle operation by the constant control relay module (CCRM) (12B581) and powertrain control module (PCM) (12A650), which will energize the cooling fan motor under the following conditions: Cooling fan motor will run at low speed: - if engine temperature is higher than normal. Cooling fan motor starts running at 106°C (222°F) and stops running at 101°C (214°F). - if A/C is on and vehicle speed does not provide enough natural airflow. Cooling fan motor starts running at speeds at or below 69 km/h (43 mph) and stops running at 77 km/h (48 mph). Cooling fan motor will run at high speed: - if engine temperature is higher than desirable and cooling fan motor has been operating at a low speed. - at 109°C (228°F) and stops running at 105°C (220°F). Sorry if this is hard to read, I can't format paragraph breaks for some reason.
Thank you for that and the readability is just fine, I appreciate you taking the time to answer.
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