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Hello,
Can someone .... that knows for sure 100%.... explain how the stock dual fans are controlled on a 1990 5.7 iroc z? I have searched the threads and i am seeing mixed answers. I would like to know the easiest way to make both fans come on earlier.
Thanks.
The easiest way to get them both to come on earlier is change the settings in the ecms prom on/offs. The secondary fan can be controlled by the ecm if you tap the green/white wire from the primary fan to the secondary relay.
primary is ecm controlled secondary is a/c request or temp head switch. Wells sw555 head switch is another option for secondary fan.
Hello,
Can someone .... that knows for sure 100%.... explain how the stock dual fans are controlled on a 1990 5.7 iroc z? I have searched the threads and i am seeing mixed answers. I would like to know the easiest way to make both fans come on earlier.
Thanks.
Just so you can see how it’s wired, it also kicks off over 35mph unless commanded.
Hey, thanks again for the picture. Looking at the drawing, am I correct that anytime the secondary fan comes on, the pcm detects that and turns on the primary? Meaning that a lower temp fan switch on the secondary would turn on both fans?
Thanks again.
I think with either a/c request of fan sw grounding the primary comes on. I like to program in the computer chip 200f on 185f off on the primary. You could test by grounding the head temp switch. You can but different on/off 3/8 single wire switch’s at summit or jegs.
I think with either a/c request of fan sw grounding the primary comes on. I like to program in the computer chip 200f on 185f off on the primary. You could test by grounding the head temp switch. You can but different on/off 3/8 single wire switch’s at summit or jegs.
I think with either a/c request of fan sw grounding the primary comes on. I like to program in the computer chip 200f on 185f off on the primary. You could test by grounding the head temp switch. You can but different on/off 3/8 single wire switch’s at summit or jegs.
Alright. I did some testing. FYI, like many of us, i am not the original owner, but car is the same as I got it.
I start the car cold, no fans. I turn on ac with temp gauge still @100 and both fans come on. I turn ac off and both fans go off. I wait for car to warm up. Driver's fan come on at about 185ish. I let idle. It stabilizes at 220. Driver's fan still only fan on. All that sounds good. Whether it's stock or some mod, I like that the both comes on with the ac. But..... I don't understand the controll circuit you uploaded for the secondary fan. If the temp switch and the ac switch were "both" normally open, it would make sense.Hi coolant temp, secondary comes on... hi ac pressure, secondary comes on.
So, what is it that I'm trying to ultimately do. I want both fans to be on at @ 220ish without the ac on. Seems just replace the switch... got it. But my ocd needs to understand how the ac switch works.
Thanks.
I recall being confused by what you outlined in yellow myself. I think what it is really trying to say is never mind, I'm still confused. Why would pressure switch open when a/c on? The idea is to provide a path to ground when fans turn on right? seems backwards.
Here is what I presume is normal operation, as my car has not been altered.
I recall being confused by what you outlined in yellow myself. What it is really trying to say is fans will shut off if pressure gets too high or turn on when temp reached. the way it is drawn is, well eh....
Here is what I presume is normal operation, as my car has not been altered.
