OOps...Electric fan wirings

[nobby911]

Hi

Hope somone can help.

Took my radiator out to have it recored unpluged the electric fan a week later i get the rad back but can't remember how to wire it up already melted an inline fuse holder so i am doing somthing wrong. I have attached a drawing of all the wires would much appreciate if some one could explain which one goes where.

Then tomorrow after i have nipped to halfords for a new fuse holder i will have another go. What size fuse should i use, the surely the old one should have blown not melted its holder

 

Thanks

 

[over_head_cam]

There should be a drawing of the circuit for the relay on the casing or on the bottom of it. Some relays are wired differently to others

 

Looks like your wiring has the stat as a switch to earth so the pos from the stat would go to one side of the solenoid in the relay, with the live spur going to he other. The main live would then go to one side of the switch in the relay, with the feed to the fan going to he other. I could be wrong though

[nobby911]

20 years since i did any of this so haven't a clue anymore lets see if i understand this correctly

 

wire 1 from the stat to 1 on the relay

the live feed to 2 & 3 of the relay

the fan then going to 4 on the relay

 

don't really understand relays so is one opposite pair a swith(say 1&2) and the other opposite pair a solenoid(say 3&4) in that case i would need to work out which pair is the switch and witch is the solenoid.

 

My apologies if i have completley misunderstood this.

[over_head_cam]

There should be a diagram on the relay

[nobby911]

I looked at the relay when i was down the garage and it had some numbers and symbols on it but i haven't a clue what they mean

[over_head_cam]

Picture

 

 

[nobby911]

i will have to look at it tomorrow its all locked away for the night now.

 

is there generic symbols to look for

 

thanks for the help

[over_head_cam]

 

IIRC the numbers are normally the same on an accessory relay

 

By the look of it yours will be:

 

main live to 86

spur live to 30

stat to 85

fan to 87

[nobby911]

thanks i will have a look at it in the morning.

 

do you have any idea what fuse should be used, because the inline fuse didn`t blow when i miswired it

 

always been scared of electrics

[over_head_cam]

I'd say a 15, or even a 10 but I'm not 100% on that.

[Copey]

13 amp should do the job

[nobby911]

Thanks for all the help.

I have printed all the instructions out and am off down the garage now to see if the theory works.

 

Going to install a new fuse holder and fuse first don't want to melt anything else

[over_head_cam]

A fuse is good

[Beakster]

Hey,

 

Here's a really good diagram:

 

 

It's not mine, its copied from: http://www.fordpower.org.uk/forum/index ... topic=5265

[nobby911]

Thanks all working again however it kept blowing the fuse everytime the fan cut in so kept increasing the size until i got to 25 amp and then all seems fine.

 

The diagram is excellent i think i will add an overide switch and dashboard light.

[Savvi]

Most fan feeds are fused at 25-30 amps

 

Rule of thumb:

 

With auto electrics:

 

+30 Battery positive feed

+15 Ignition positive feed

 

The idea of a relay is to connect heavy high power cables together by using a lower current cable so as to be able to have smaller switches which will not burn out by over loading them.

 

 

On most relays:

 

Pin 30 is the supply to what ever your looking to feed,

( can be live or earth)

Pin 87 is to the accessory, be it fan, lights etc.

(will be live or earth depending on pin 30)

Pin 85 is the earth side of the coil of the relay.

Pin 86 is the live side of the coil of the relay.

 

When power and earth are joined via the internal coil (pins 85 & 86) it creates an electro magnet to pull a contact in to join pin 30 & 87.

 

This could also be used to break a connection with another pin normally 87a

 

 

Not trying to teach people who know, but this may make the novices to understand the principle of how a relay works and why it's there ?