[Mk2] [NA] Wiring in extra fans on a toggle switch?

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grainge231
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Joined: Thu Feb 20, 2014 10:16 pm

[Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by grainge231 »

Hi does anybody have any idea how I would wire in electrical fans onto a toggle switch? Will I need to fuse these fans use a relay ect. I tried looking for a generic wiring diagram for electric fan set up and couldn't find much. If anybody has any advice that would be great. Thanks :)
shinny
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Location: Reading, UK

Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by shinny »

Use a relay... the PO of my car wired the rogue fans directly through a switch and it got so hot it would burn your leg! #-o
grainge231
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by grainge231 »

Yeah from what I've managed to find online I need to go with a 30amp fuse and a relay. I'll post pictures when I start this in case anybody else needs a guide.
shinny
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by shinny »

grainge231 wrote:Yeah from what I've managed to find online I need to go with a 30amp fuse and a relay. I'll post pictures when I start this in case anybody else needs a guide.


There must be a guide already.. maybe not specifically for an MR2, but it's not the most tricky of wiring jobs.

Where are you placing the fans?
tiff_lee
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by tiff_lee »

Live from battery to fuse to relay, from relay to your fans. I would jumper from the supply feed terminal to the coil of the relay then run a switched earth to turn the relay on and off.

Edit:
I did try to link an image but still unable to because not enough posts, yawn

Pin 30 supply from battery (via fuse)
Pin 87 to your fans
Pin 85/86 Live & earth for relay coil, personally I would jumper the live from pin 30 and then run a wire to your switch and earth the switch (so your switched earth will energise the relay).
shinny
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Location: Reading, UK

Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by shinny »

Mostly good but...

tiff_lee wrote:Live from battery to fuse to relay... I would jumper from the supply feed terminal to the coil of the relay then run a switched earth to turn the relay on and off.


Personally wouldn't do that. I would either:
a) use a switched live as a power source
b) find a switched positive behind the dash and switch that to activate the relay

The reason being that fans are great at draining batteries and I've seen it done on meets. I would suggest that making the fans only operate on the ignition is a very wise precaution!
tiff_lee
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by tiff_lee »

By switched live I assume you mean ignition? I won't argue that it's a good safety precaution I just never anticipated someone turning the car off but leaving the fans on, was just to save running another live wire into the car if not necessary.

Are these fans for the engine bay or radiator? Ideally you would just have a temperature sensor to trigger the relay and remove the 'manual switch' thing, just as Shinny has seen people leave them on I have seen people forget to turn them on.
shinny
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by shinny »

tiff_lee wrote:By switched live I assume you mean ignition?


I do

tiff_lee wrote:I won't argue that it's a good safety precaution I just never anticipated someone turning the car off but leaving the fans on, was just to save running another live wire into the car if not necessary.


Noone would intend to do so... but easy to forget

tiff_lee wrote:Are these fans for the engine bay or radiator? Ideally you would just have a temperature sensor to trigger the relay and remove the 'manual switch' thing, just as Shinny has seen people leave them on I have seen people forget to turn them on.


This is the thing.. both the rad and the engine bay have temperature controlled fans already. Hooking into either of these systems is a better idea that a switch IMHO.
grainge231
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Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by grainge231 »

Well my fans don't kick in at all even when the temp gauge is red hot. And one of the previous owners has hacked the wiring and spliced it with something :/ so was just going to wire in a manual switch as I'll mainly be using the car for trackdays and not a daily driver. Also adding an extra fan into the engine bay Which again I'm thinking of toggle switching
grainge231
Posts: 68
Joined: Thu Feb 20, 2014 10:16 pm

Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by grainge231 »

Would it be an idea to try and pick up from the original loom somewhere and just add an override switch to take over from the temp sensor which isn't cutting in.
shinny
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Location: Reading, UK

Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by shinny »

grainge231 wrote:Would it be an idea to try and pick up from the original loom somewhere and just add an override switch to take over from the temp sensor which isn't cutting in.


Or just fix the stock system?
grainge231
Posts: 68
Joined: Thu Feb 20, 2014 10:16 pm

Re: [Mk2] [NA] Wiring in extra fans on a toggle switch?

Post by grainge231 »

Is it likely to just be the temp sender? Or relay? Or something else really not got a clue when I comes to electrics. The engine bay fan doesn't seem to engage either which is what puzzles me? I'm assuiming they're not on the same circuit?
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