Thermo fan set up

billyvanboheman · Post by **billyvanboheman** » Mon Aug 13, 2007 4:28 pm

I'm in the middle of an electric fan mod and am looking for some info on which way the wiring should work.
I have inherited a fan and thermo switch set up out of a Mitsi, what I need to know is does the thermo switch work by closing the circuit on a ground wire, or is it making a live wire when closed?

I can rig it up and test it, but would prefer to get an opinion before trying to fry it!

cheers

dazza85 · Post by **dazza85** » Mon Aug 13, 2007 5:03 pm

If the thermo switch is a single wire it will go to ground, if it is a 2 wire it can go either / or ...

I'll do a sketch when I get home then others can tell me where I've gone wrong then we will both be better off. :lol:

billyvanboheman · Post by **billyvanboheman** » Mon Aug 13, 2007 6:03 pm

cool, mine is a two wire switch, and I stick to my moto, I HATE auto electrics :!:

BIG_BOY · Post by **BIG_BOY** » Mon Aug 13, 2007 6:22 pm

heres how i would do it it gives you safty added cooling when desired & stops water from rivers going every were when need but is still unable to be for got in after the river is over

try this

billyvanboheman · Post by **billyvanboheman** » Mon Aug 13, 2007 6:36 pm

I was half way through drawing a pic of my own, but it was not as flash as yours, I am on the same track, but a little less thorough in the switching department.
I have a rocker switch mounted in the console between the seats, so that when the fan is switched off it runs a big red flashing light above the temp gauge.
I've never got the whole relay thing though, so hadn't planned on one, can you fill me in on it, in layman's terms?

dazza85 · Post by **dazza85** » Mon Aug 13, 2007 6:50 pm

Big_boy had the right idea ... but his hot weather override switch was in the wrong place ...
I'm picking thats why he pulled it ...

The relay handles the current load of the fan (or spots, horns, etc)
this means you can use lighter wire and smaller switches to control the equipment.

billyvanboheman · Post by **billyvanboheman** » Mon Aug 13, 2007 6:56 pm

dazza85 wrote:The relay handles the current load of the fan (or spots, horns, etc)
this means you can use lighter wire and smaller switches to control the equipment.

I see, so heavier cable for the power to the relay and onto the fan, then lighter cable to run all the switching :?:

BIG_BOY · Post by **BIG_BOY** » Mon Aug 13, 2007 6:56 pm

yeah that was why i took it off but its back now all fixed

also a relay in the right place will add 20-35% more profamance to a eletric fan over a switch that flicks the current

BIG_BOY · Post by **BIG_BOY** » Mon Aug 13, 2007 6:58 pm

billyvanboheman wrote:
dazza85 wrote:The relay handles the current load of the fan (or spots, horns, etc)
this means you can use lighter wire and smaller switches to control the equipment.

I see, so heavier cable for the power to the relay and onto the fan, then lighter cable to run all the switching

yep you got that way the cables for the power are shorter & have less joins breaks so there is less V.D. so it fan gets more volts & current so it works better

Mattman · Post by **Mattman** » Mon Aug 13, 2007 7:28 pm

If the joins are properly made and the right size wire is used there will be no voltage drop.

Running 20-30 amps through a switch though is not a good idea, you will burn it out quickly and also have a big point of failure.

Also you want to use a normally closed relay if possible to power the fan, that way if the sensor or your switch fails the relay will default to closed and will power the fan.

If your sensor doesn't allow this then you need to use two relays, use the first relay to invert the signal from the sensor so you can then drive the second relay which drives the fan.

Matt.

niblik · Post by **niblik** » Mon Aug 13, 2007 7:33 pm

bah..

electrical this... join that.. connection voltage whats-it-ma-jiggy those....

i read it, but all i'm makin out is 'wa wa waaa wa wa waa waaa wa waa'

viscous fan! now thats where its at.. :wink:

kiddin.. nice form dude.. what about the disco dash light? gonna update this thread about that? (in the background with the smoke machine... doof doof doof doof doof... ) :roll:

dazza85 · Post by **dazza85** » Mon Aug 13, 2007 10:07 pm

I hope Big Boy doesn't mind I pinched his pic,

I like his idea of a pushbutton that your passenger holds down but I often don't have one. They often seam to bail on me ... I'm not sure why

Any way if you replace the pushbutton with a 2 way toggle ( it has 3 tags out the back) when the fan is not on the light is.

If this don't make sense pm me your phone no and I'll see if I can make it clearer

billyvanboheman · Post by **billyvanboheman** » Mon Aug 13, 2007 11:49 pm

Does any of the Electricery experts see any issues with my idea for the Electric fan wiring.

I take on board the idea about the normally closed relay, but have gone with the open option.

Any input appreciated.

dazza85 · Post by **dazza85** » Tue Aug 14, 2007 7:14 am

That looks spot on.

wjw · Post by **wjw** » Tue Aug 14, 2007 8:06 am

This is what I'm doing. No light but I have On - Auto - Off, using heavier wire, no relay for the switch only for the Thermo control module..

BIG_BOY · Post by **BIG_BOY** » Tue Aug 14, 2007 10:20 am

WJW you cant have an auto with out a relay the temp senders handle 1A max theres no way you can draw 20-35A thro them

wjw · Post by **wjw** » Tue Aug 14, 2007 11:20 am

BIG_BOY wrote:WJW you cant have an auto with out a relay the temp senders handle 1A max theres no way you can draw 20-35A thro them

Oops sorry yes .. hold on I'll change it.

BIG_BOY · Post by **BIG_BOY** » Tue Aug 14, 2007 1:17 pm

WJW that still wont work id sujest you go with the plan me or dazza have put up cos at the moment your relay wont trigger & also when you bypass the relay you will be putting alot of current thro the switch witch isent a good idear as that will creat a V.D. in the switch normaly & also you have know way of putting a light in for when its off so if you knock it will be all over for you motor