If the cooling fans are not working, the temperature would definitely go up at idle. When moving, the moving air is able to cool the radiator therefore the temperature migt not go up, at least not when runnig at high speeds.
Cooling fan is controlled by the Digital Motor Electronics (DME) control unit, located at front of radiator, and if there are any fault with it, the fans would not be commanded to come on when required.
Our database does not have any information on the testings and diagnostics of the system so I my assistance would be limited.
Sunday, October 30th, 2011 AT 7:18 AM