I suspect my high fan isn't switching on. Note that I'm running an AEM-EMS. However, if I ground pin 17 with a cold engine should I expect the fan to come on or would it only come on at or above its set temperature? It doesn't come on (cold) but there is a "click" sound as if a relay is being triggered. If I run power to the high pin on the fan motor connector it does run. Same with power to the low fan so we know the fan motor is good. Hissin50 are you still lurking about?