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2G Wiring both fans to run together

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Kai Hefner

Freelancer
480
272
Jun 21, 2018
Calgary, AB_Canada
To preface this question, I will likely be deleting my AC soon. Blah blah comfortable driving whatever; I'll drive fast and roll the windows down.

For clearance issues with a new radiator, I was looking to keep one fan pulling, and one fan pushing. Are there any problems with wiring these two fans to turn on together? Was thinking of maybe putting in seperate switches in the cabin for each fan but is there an issue with cooling the car too much?
 
This is what I do.
Assuming the OP's car is 2g, not 1g.
Use a short wire and make the two terminals connected on the fan relays between the green circles in the attached pics. With this way, the A/C fan will automatically be triggered via the factory a/c fan relay when the radiator fan gets turned on by ecu (no need to turn on the A/C). And you can install a switch between the two red circles if you don't need the A/C fan always.

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I like that wiring, I might try that, thank you for the responses.

I should probably clarify my question, both fans will have their own wires. I was thinking of wiring them independently to two switches in the cabin (one for each fan). Is there any problem with having both fans on at all times? Can my car be cooled too much?
 
You can run both at the same time, I have to myself. I run the pusher with the A/C button and its relay and run my puller on the stock 1g setup also. I used to have a 3rd fan and it had a separate switch/relay. Got too crowded so took it out and went with 2 big Spal fans. I would suggest a good fan, not the cheap Ebay fans that "claim" to move "X" amount of air but really don't.
 
Yeah I will be switching to SPAL soon enough, have these Mishimoto slim fans that came with the car. I thought they were ebay special fans at first but god damn it seems like they move air. Sounds like a fighter jet when I'm parked and have the fans on.
Regardless, you answered my question, can't really have too much cooling LOL
 
You can turn the fans on at any temp, rpm, boost etc that you like if you have ecmlink. I wouldn't run them all the time because you're just needlessly putting wear and tear on the fans.
 
This is what I do.
Assuming the OP's car is 2g, not 1g.
Use a short wire and make the two terminals connected on the fan relays between the green circles in the attached pics. With this way, the A/C fan will automatically be triggered via the factory a/c fan relay when the radiator fan gets turned on by ecu (no need to turn on the A/C). And you can install a switch between the two red circles if you don't need the A/C fan always.

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Hijacking Kai's thread, thinking of running two stock AC fans and making them turn on at the same time. The blue wire you installed, is that just pressed into the relay holes so it gets sandwiched? Did you solder them, or use some sort of thin spades? I'm worried of it coming loose and possibly shorting or busting relays. Then again I'm really bad with electrical stuff.
 
Hijacking Kai's thread, thinking of running two stock AC fans and making them turn on at the same time. The blue wire you installed, is that just pressed into the relay holes so it gets sandwiched? Did you solder them, or use some sort of thin spades? I'm worried of it coming loose and possibly shorting or busting relays. Then again I'm really bad with electrical stuff.
It looks like it's just sandwhiched din there which should work.
 
Hijacking Kai's thread, thinking of running two stock AC fans and making them turn on at the same time. The blue wire you installed, is that just pressed into the relay holes so it gets sandwiched? Did you solder them, or use some sort of thin spades? I'm worried of it coming loose and possibly shorting or busting relays. Then again I'm really bad with electrical stuff.
It's sandwiched and it's just a trigger wire. You don't need a thick gauge wire. so it doesn't bother the relays much, actually the relay terminals have some extra room that the wire goes in. Like 14 or 16 gauge wire is fine. I don't feel a need to solder for this but this is a wiring work, so a solid answer for it would be yes, you should solder the wire behind the fuse box directly on the harness side if you are worried. That would be your call.
 
It's sandwiched and it's just a trigger wire. You don't need a thick gauge wire. so it doesn't bother the relays much, actually the relay terminals have some extra room that the wire goes in. Like 14 or 16 gauge wire is fine. I don't feel a need to solder for this but this is a wiring work, so a solid answer for it would be yes, you should solder the wire behind the fuse box directly on the harness side if you are worried. That would be your call.
Thanks Hiroshi. I actually did this last year when you explained it and it did work (but I never replied :( ). However now I want to do the AC switch mod where you wire it to pin 20 on the ECU and ground the other wire. This mod allows you to force ON both fans by clicking the AC button. Do you think it would clash in any way with the relays being connected by the wire?
 
I'll chime in and say that as long as the ECU or switch is just pulling to ground and assuming each fan has a relay, that will work. My 1g works that way.
Sorry to butt in.
 
This is what I do.
Assuming the OP's car is 2g, not 1g.
Use a short wire and make the two terminals connected on the fan relays between the green circles in the attached pics. With this way, the A/C fan will automatically be triggered via the factory a/c fan relay when the radiator fan gets turned on by ecu (no need to turn on the A/C). And you can install a switch between the two red circles if you don't need the A/C fan always.

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Bringing this thread back alive. If you were to wire a switch on the two red circles, would you still need to run an inline fuse or would the fuse in the fuse box work already. I plan on getting a spal fan soon and want to make the wiring as simple as i can to not make a mess in my engine bay. The spal fan I will wire to connect with the oem condenser connector to make maintenance and removal of fan simpler.
 
I used the AC button to trigger the fans:

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Okay awesome, I am a bit concerned if this would still work with AC as I still have all my creature comforts. Electrical isn't my forte 😅

I did find the write up by Todd to wire the AC fan only to a switch as stated above in this post. I think I'll wire to a switch preferably as I don't want to mess with the harness or ECU wiring, thanks for the video drew!
 
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If you were to wire a switch on the two red circles, would you still need to run an inline fuse or would the fuse in the fuse box work already.
The red circle 12v should be coming through 20A fuse. So as long as if the switch is capable to handle that current, it shouldn't be a problem.
 
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