Radiator fans

The fans are controlled through the ECM. They respond to temperature and AC activation. Normally at least one fan activates when you turn on the AC to ensure airflow across the condenser and allow the AC to operate even if the vehicle is not moving. The other fans and speeds are controlled by the temperature and the ECM. If the temperature is right at the edge of fan activation it will turn them on, then recalculate that it did not need them and turn off. Most multi-speed fan systems work in the same way, there are relays that toggle to run the fans. Low speed runs both fans in series, that means each one is running at about six volts and half speed. Then once the temperature goes up the relays shift and now both fans get a full twelve volts and run at high speed. Some AC systems use both fans, others will only turn on one at full speed. It sounds like your system is working okay if this happens when the engine is warmed up fully.

You are welcome. I have had similar things with the Journey, The fans will turn on for maybe a second, barely get up to speed then turn off, When I look at the actual coolant temperature it is right on the edge of the on temperature.

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