The information you read about vehicle has to be running for the fans to work is wrong. In fact it is the reverse, up to a certain point. When vehicle is not moving, the coolant in radiator would heat up as well and this would require the fan to work to reduce the heat of the coolant.
When vehicle is moving, air flow is able to help cool the radiator resulting in less use of the cooling fans.
Do the fans come on when A/C is turned on?
When does the overheating occur?
Do you have coolant losses issues?
Is lower radiator hose very much cooler than the upper hose?
Radiator fans are controlled by the engine computer via signals from the Engine Coolant Sensor and if the fans are not coming on, it could be a faulty computer.
Thursday, December 6th, 2012 AT 1:47 PM