<span class="highlight">Wiring</span> to 12 volt relay switch

Submitted: Wednesday, Nov 14, 2007 at 18:31
ThreadID: 51601 Views:8011 Replies:6 FollowUps:0
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I am hoping one of you good people can help me with this.
I am wiring an electric fan to my intercooler. I have the wiring to the relay as per the manufacturers instructions but am uncertain about the on/off switch I am fitting.
The switch has 4 pins.
1. Power 2. Earth 3. Accessories 4. Relay switch.
I have the power source from an accessories that is connected to the ignition & tried connecting the relay from the switch relay pin (No success) when I connected the switch earth pin to the relay it activated.
What my main concern is this correct or am I likely to have problems.
Would appreciate any help.
Thanks
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Reply By: F4Phantom - Wednesday, Nov 14, 2007 at 19:12

Wednesday, Nov 14, 2007 at 19:12
I dont really understand what you have done but may be able to explain what you need to do.

2x of the relay pins are to connect and break the main power circuit for the fan and the 2x smaller pins is to supply a current to allow the relay to make that connection.

The large power wire usually + (some cars are reversed like my nissan) is cut so a circuit for the fan is not connected. At the cut you have made in the + power wire connect each side to the two main pins on the relay. This is the + supply wire, the - supply wire is connected directly to the fan. Now the relay has power to connect when its activated.

Now you have to run another circuit to activate the relay by applying power. So run a negative wire straight to the one activation pin on the relay, then run a + wire to 1. the switch on the dash and 2. to the other relay pin.

Now when you push the dash switch you connect a cuircuit to the relay, the relay then powers up and connects the large amp cuircuit which then supplies power the the fan.

I just read over my instructions and cant make to much sense of it so good luck. BTW buy a pajero where that fan you are instaling has been standard for 20 yrs!
AnswerID: 271728

Reply By: Member - Graham H (QLD) - Wednesday, Nov 14, 2007 at 19:37

Wednesday, Nov 14, 2007 at 19:37
Try this link
http://rides.webshots.com/photo/1051308620031720211TostwD

If its the swtich u r having probs with all u need is a feed from the battery or somewhere to a 2 pin switch, in one side out the other to the relay. Unless u have a light in it u dont need anything else
Reading your post I would think its Power from wherever to power accessories to relay nothing else is needed as you are just turning the power on or off to activate the relay not the power to activate the fan That is done from the relay.









Google is a marvelous tool, sadly under used
AnswerID: 271733

Reply By: Philip A - Wednesday, Nov 14, 2007 at 20:08

Wednesday, Nov 14, 2007 at 20:08
My guess is that the switch you have bought has a light in it.
accessories and earth are for the light.
Power and relay are for the switch.
Regards Philip A
AnswerID: 271743

Reply By: Member - Olcoolone (S.A) - Wednesday, Nov 14, 2007 at 20:24

Wednesday, Nov 14, 2007 at 20:24
What is the wiring if he used a diode protected relay.
AnswerID: 271747

Reply By: Old Johno [NSW] - Wednesday, Nov 14, 2007 at 22:29

Wednesday, Nov 14, 2007 at 22:29
Thanks for the replies but maybe I didn't explain my self properly.
I have the relay connected as per the wiring diagram but the switch I am using to activate the relay is my concern.
When I have connected a power supply I used an accessory supply connected to the ignition to enable the fan to be cut off as soon as the ignition was turned off. When I Had the power supply on and the feed to the relay connected to the relay switch pin the diode light was on but the relay was not activating. However when the power supply was on and the relay was connected to the earth pin the relay activated and the diode light came on so my main query was is this OK for the switch.
Thanks
AnswerID: 271773

Reply By: Member - Smithy (VIC) - Wednesday, Nov 14, 2007 at 23:07

Wednesday, Nov 14, 2007 at 23:07
G’day Old Johno


I have just installed the same thing in my patrol, all I did is

Cable from Batt + thru a 10 amp fuse to relay pin (30)
From pin (87) on relay to fan, other wire on fan to earth
From relay pin (85) to earth
Power from wiper motor to switch
other side of switch to relay pin (86)

in my case I used a thermal switch (50c) so I don’t need a switch in cabin



Hope it helps ya
AnswerID: 271780

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