I would like to find out how to hook up my secondary fan to activate once the primary fan starts up. However I don't want to have to deal with a manual switch. I've read numerous postings and still are not quite sure how to accomplish this task. If someone could please provide detailed instructions it would be greatly appreciated. Thanks

 

basically splice in a jumper wire from the two F wires on each relay.



so when the ecm grounds the drivers side relay, that same ground signal will ground the passengers side relay and both fans should be on when the drivers side comes on.