Originally Posted by Paul1958
I have an 02 wagon with the Zetec. When the vehicle does not have the AC on the cooling fans are commanded on/off by the PCM mainly by the input from the cylinder head temperature sensor (CHTS) which is located in the cylinder head near the alternator. They do fail and when they do the typical system response is erratic or no cooling fan operation. The sensor is a huge PITA the change (alternator has to be partially removed) so I would try to test it first. Im not sure what the resistance is supposed to be at various temps.
Thank you! I guess I'll quickly look them up, (and put my findings here). It seems my fans work quite oddly then...darnit