Anyone good with wires?

[Big Daft Lad]

OK electrickery scares me, even on cars!

Could someone tell me how to wire in (or better still draw me a diagram) a basic radiator fan loom?

I don’t want anything fancy just a switch on the dashboard for manual operation.

Do I need a relay as well as a fuse?

TIA.

Edited by Big Daft Lad on Friday 25th September 19:08

[B@man]

Are you just wiring up an override for the existing fan or are you replacing the existing set-up with a simple switch & relay affair ?

[Wedg1e]

Yep, try this:



The numbers 30,87 etc. relate to the terminals on a typical automotive relay.

Fuse should be big enough to cope with surge current of fan motor, say 20A.

Edited by Wedg1e on Friday 25th September 21:28

[rev-erend]

Ian's diagram may initially look complicated ..

butr in essence - all a fan or most anything else needs is :

a 12 volt positive feed ..

this will not work until it has an earth to complete the circuit.

Normally the earth is switched - either manually or by say an otter switch (when the water gets otter it switches on the (-) feed to the fan).

A slight complication to this is the big amount of current (amps) involved - so a relay (electronic switch) is used to rapidly turn on/off the current to save the switch arcing out and burning out.

[Deva Link]

Wedg1e said:

Fuse should be big enough to cope with surge current of fan motor, say 20A.

A vital thing is to make sure the wire used has a rating well in excess of the fuse rating (think 3mm, 27.5A is a car wire rating) so that, in the event of a fault, the fuse will blow before the wiring melts!

[pwd95]

Or just extend the 'otter' wires to the cockpit with a manual switch on the end. But you must remember to put them on!!.

[Wedg1e]

Deva Link said:

Wedg1e said:

Fuse should be big enough to cope with surge current of fan motor, say 20A.

A vital thing is to make sure the wire used has a rating well in excess of the fuse rating (think 3mm, 27.5A is a car wire rating) so that, in the event of a fault, the fuse will blow before the wiring melts!

Good point.

[Big Daft Lad]

Thanks all, got something sorted out today.

[jmorgan]

pwd95 said:

Or just extend the 'otter' wires to the cockpit with a manual switch on the end. But you must remember to put them on!!.

Ok, OK, I will wire the temp sensor in one day..........




just don't fancy the prospect of getting at the ignition side battery bits on the fuse panel.....

[GV]

You can pick up Kenlowe kit complete with switch, relay, diagram temp probe off ebay for £40. If you don't need a temp probe you can use the existing otter switch feed into a switch and it will do the job.