I have a 1988 Iroc 5.7 with dual cooling fans.I have both green/white wires rigged up to separate toggle switches to turn on one fan or both fans.Why do the fans not come on automatically?I have replaced the fan switch for the secondary fan twice and still nothing and checked the green/white wire for the primary fan back to the ECM terminal C1 and it is good.It seems like neither fan is receiving a signal to trigger it.What could cause this?Is it possible the temp guage is that far off even when it is in the red the engine is still not hot enough to trigger the fans?Thanks for any replies.

 

 

Secondary fan turns on.The switch has been changed 3 times and still nothing.Maybe the cheap connecter that keeps on melting loses contact with the switch.

 

If you are using the green/white wire make certain the switch is not inline with the green/white wire, if it is then that is your problem. The green/white wire is trigger wire for the relay and only needs a few amps at most. You want to splice in or solder into the green/white wire another wire, two wires going into one. I believe that the ecm grounds out the relay with the green/white wire, so you would want that wire to be a switchable ground.
Look at this page:
http://www.bcae1.com/relays.htm

 

All original wiring intact.All I did was splice a single wire from the green/white wire on the primary relay to a switch inside the car and a wire from the switch to ground.Did the same for secondary relay.This way I can turn on primary fan or secondary fan or both at the same time.Relays ,fuses and wiring unchanged and non powered switches.Also this way there is no power to the fans with key off so if you forget to turn them off it won`t matter because when you turn the ignition off the fans will shut off and not drain the battery.