i must have missed it in my search, i had my ECM reprogramed for electric fans on my 02 4.3 k truck. they guy who did the programing was not able to tell me which to terminals on the ecm need to be wired up to make the low/high fans turn on. far as im aware, a truck WITH electric fans from the factory uses differnt terminals the a PROGRAMED ecm. that is my understading. please correct me if im wrong.