Radiator Fan Cutoff Switch

UnrealPaprika

UnrealPaprika

New Member
Joined
Sep 15, 2019
Messages
3
Location
Michigan, United States
Car Year
2005
Car Model
Forester 2.5X
Transmission
Manual
I know that this is a topic that has been covered before, but every time I try to research it I run into dead ends or people who did things just a but differently than I want to. I want a switch so that I can manually turn the cooling fans off or leave them in the default automatic mode. Every post I have found thus far either has pictures that no longer exist (thanks photobucket) or wiring diagrams that aren't quite for what I want. Hopfully someone out there who has done this can either provide a wiring diagram for what I want or even better pictures of how they wired it. The main problem for me is that I'm not very good with wires so I can't just look at the default wiring diagram and know where to splice in the switch. Thanks in advance. I have an '05 Forester 2.5x if that makes any difference.
 
@UnrealPaprika As I wanted to keep the original wiring intact I spliced into the leads near the radiator and redirected the ground / earth to 2 normally-on relays and then to ground. Then I ran to a single switch in the cabin. Long way around know but the intent at the time was to simply remove any additional circuitry without trace in future. I imagine you could probably hook something up to the fan relays in the main fuse block; do you have the circuit diagrams / workshop manual?
 
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Welcome to the forum, @UnrealPaprika!

I would do the same as what Kevin did as the switch would be between the radiator fan and the relay - less intrusive. That way if the fan is turned back on again, it would just revert to the normal fan operation. Cheers.
 
Make sure that you have a warning light or similar that tells you that your fans are OFF.

Otherwise, it is possible to cook your engine ... :(
 
Buzzer is an excellent idea.
 
Thanks guys. I did find a wiring diagram that I believe is accurate. It seemed to me to be simplest if I chopped the wiring right behind the fans and interrupted the positive power there using a switch. Then if I had the correct switch I could have it power a buzzer instead of the fans. Maybe I should do it on the other side of the relays though.
 

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The other thing I would appreciate is either diagrams or pictures from people who have done it. Thanks
 
yes pictures are best thing ever, just show us what you did with what tools and what is result in simple collage maybe or smt. i all ways find that most informative for me, not words, as we not all native eng speakers here some words could be just too specific and not known by all.
 
I've not forgotten this - pics probably not that useful when everything is covered in tape. I'll get a diagram up eventually.
 
This is a good way of doing it: https://www.offroadsubarus.com/threads/fan-cut-off-switch.2020/#post-20135

While revisiting this I've discovered that I've switched the positive feed from the main relays; not sure why but it works!
I'm actually replacing some old connections on mine atm that were recently damaged so I may rethink it.
So the current setup is that I've added 2 x normally-on relays (30 amp) to switch the fans. I've interrupted the positives from the OEM relays. I found that the sub-fan, not the main fan, is White / Blue the main fan then I guess is supposed to be Yellow / Black but cannot guarantee it as it's covered (will update later if I can confirm). A single switch wire is jumped between the added relays and runs into the cabin to a single pole switch which illuminates when on. Without pulling everything apart to confirm, I believe the power for the switch is taken from the cigarette lighter in the centre console.

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Relays are positioned on the strut tower
Relay Position.jpg

Relays.jpg

This is where I break into the circuit at the sub-fan under the radiator (WIP today). (The Narva Solder Splice connectors are very convenient; just use a heat gun and the solder melts and the sleeves are shrink-wrap)

Wiring Connection.jpg

The switch

Switch.jpg

Here's how it all hangs together - I hope it makes some sense!
Fan off Circuit.jpg
 
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Man never thought this switch is so complicated, i would do it simpliest way there is.
 
You ought to look at the (very neat) bodgie job I did on my lightbar ... :poke: :nod::lol1:.

But it's worked without problems for many years now ...
 
Yes i would like to see that. Is it still availiable?
 
Kevin said:
Yes, pull the fuse ;)
Click to expand...
No i thought more of simple way to make switch just cut wire add switch, maybe relay, maybe fuse . Done. what if add switch to ground wire not voltage? Then just switch needed no?
But you need to have snorkel first if you afraid of that going into water are you?

Or make switch from fuse with added same fuse to it then just make wires from fuse to switch and add same fuse to that.
 
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