[SierraDan]

I'm installing a 10" thermo to the front of my Sierra and have the daves Craig thermatic switch.

I was wondering if simply having a switch connecting before and after the daves Craig switch to turn it on when I want it on, would work?
Or would a relay or something need to be included to close off power to the daves Craig switch?

Cheers

[royce]

having a switch would work, however if the thermatic switch is setup properly youll never need a switch

both still need to be switching a relay that then powers the fan, the thermatic switch isnt designed to carry that much current

[matfan]

royce wrote:

having a switch would work, however if the thermatic switch is setup properly youll never need a switch

both still need to be switching a relay that then powers the fan, the thermatic switch isnt designed to carry that much current

Having the switch is good for water crossings though....

[JrZook]

If you needed it id go:

Thermo switch -> relay->fan

Then to add an overide switch id go +12V ignition to relay trigger coil, then on the other side of the trigger coil to a switch then to ground.

Thus with the switch closed (on) normal operation of the thermo switch occurs, switch open relay doesn't activate and therefore no fan.

[shep]

do you still have the mechanical fan? i don't reckon a 10" jobbie would be big enough on its own.

[SierraDan]

royce wrote:

having a switch would work, however if the thermatic switch is setup properly youll never need a switch

both still need to be switching a relay that then powers the fan, the thermatic switch isnt designed to carry that much current

Yeah I'm using a relay for sure. I'm running the thematic switch as per instructions between ignition and the relay.

[SierraDan]

shep wrote:

do you still have the mechanical fan? i don't reckon a 10" jobbie would be big enough on its own.

Yeah still running the crank fan. Just putting the thermo on for the low range battles in the hot bush.

[SierraDan]

JrZook wrote:

If you needed it id go:

Thermo switch -> relay->fan

Then to add an overide switch id go +12V ignition to relay trigger coil, then on the other side of the trigger coil to a switch then to ground.

Thus with the switch closed (on) normal operation of the thermo switch occurs, switch open relay doesn't activate and therefore no fan.

That's sounds pretty good to me! Cheers

[royce]

you lot havent paid attention have you

Question was a switch either side of thermatic switch, IE manaul over ride to turn the fan ON

you lot are talking about turning the fan OFF

Best way to overcome this is an on-off-on toggle switch, centre pin of the switch to the relay trigger, one side to earth, other side to teh thermatic switch (which has it other pin earther so you are switching the earth of the relay like Jnr mentions)

then you can have auto, manual on or off with one switch

[JrZook]

royce wrote:

you lot havent paid attention have you

Lol what the point of being able to turn it on when you want if you already have a thermo switch control? Unless the thermo switch dies....

Mr OP enlighten me

[SierraDan]

Now that I'm thinking about it. You're right . My dad brought it up last night and I queried correct wiring.

But I reckon I'll have an off switch. Seems to make MORE sense.
Don't mind me, just having a retard moment.

[royce]

I personally dont see the need for an override OFF switch, once the radiator gets submerged enough to warrant stopping the fan from turning the engine temp will drop enough that the switch wont switch anyway

[SierraDan]

But don't you turn it off before you drive in?

[Fatzook]

SierraDan wrote:

I'm installing a 10" thermo to the front of my Sierra and have the daves Craig thermatic switch.

I was wondering if simply having a switch connecting before and after the daves Craig switch to turn it on when I want it on, would work?
Or would a relay or something need to be included to close off power to the daves Craig switch?

Cheers

Best of luck with that. Mine failed 3 days after fitting it. It made it 2 days into a trip to fraser before it fucked me over. I'll never buy their cheap chinese shit again.

[Fatzook]

SierraDan wrote:

But don't you turn it off before you drive in?

Thats best practice.

Royce is correct to a point. Problem with relying on the thermo switch to shut the fan off once the motor is submerged is that the fan blades may have already flexed and started munching on you radiator core by then.

[royce]

Fatzook wrote:

SierraDan wrote:

But don't you turn it off before you drive in?

Thats best practice.

Royce is correct to a point. Problem with relying on the thermo switch to shut the fan off once the motor is submerged is that the fan blades may have already flexed and started munching on you radiator core by then.

Am I the only one that remembers the let your junk cool down a bit before entering deep water so things dont cool and suck in water rule?

So therefore you arent entering water with the fan anywhere near looking like its going to turn on

[SierraDan]

So do you think I should just wire it up without the thermatic switch?

[Fatzook]

SierraDan wrote:

So do you think I should just wire it up without the thermatic switch?

No. You still need one. Its not good to run a thermo 24/7, and if you are switching it on as required there is a good chance you will forget at some point and boil your motor.

[Fatzook]

royce wrote:

Fatzook wrote:

SierraDan wrote:

But don't you turn it off before you drive in?

Thats best practice.

Royce is correct to a point. Problem with relying on the thermo switch to shut the fan off once the motor is submerged is that the fan blades may have already flexed and started munching on you radiator core by then.

Am I the only one that remembers the let your junk cool down a bit before entering deep water so things dont cool and suck in water rule?

So therefore you arent entering water with the fan anywhere near looking like its going to turn on

I agree. But its still useful to have an override switch.

[SierraDan]

Ive only ever done one water crossing. I'm a rock sort of guy. I just like having an option. I think I'll leave a switch out, as it is likely to be a blue moon that it'll get switched. I'll just have a plug in the circuit so the option is available.

[Fatzook]

SierraDan wrote:

Ive only ever done one water crossing. I'm a rock sort of guy. I just like having an option. I think I'll leave a switch out, as it is likely to be a blue moon that it'll get switched. I'll just have a plug in the circuit so the option is available.

Don't even bother with the plug. You can always get out before you do the water crossing and pull the power supply connector off the thermo switch.

[SierraDan]

I haven't even looked at it yet to be honest. So are they the same sorta connectors a spotlight would have?

[Fatzook]

SierraDan wrote:

I haven't even looked at it yet to be honest. So are they the same sorta connectors a spotlight would have?

The davies thermo controller switch will just have blade terminals. So you just need to pull a wire off to stop it from working. Thats if it doesn't shit itself first.

[SierraDan]

Ah cool. That'll do me then!
So what part if it shit itself?

[Fatzook]

SierraDan wrote:

Ah cool. That'll do me then!
So what part if it shit itself?

I bought an "ICE" brand one from repco that lasted quite a while. It didn't fail, but I replaced it with an electronic therm contoller. Has a digi screen in can and runs off an OEM electric probe type manifold sensor instead of the capilery style 'up the radiator hose' ones that the davies and ICE ones do. Heaps more $$$ though

[SierraDan]

That's what I thought it ran off, the water temp gauge switch thing. I don't really like the idea of the probe thing up the hose.. Seems unreliable.

I'll run with what I've got and upgrade accordingly if it doesn't perform.

Thanks for your help guys.

[31zook]

start wire>switch (with light for on)>thermo sensor>relay>fan.

thats how i did mine

[31zook]

PS: mine dosn't really need any fan, apart from 40deg days and reving with load on rocks...... I have a 1.6 bigger vit radiator, and a worked 1.3 engine, always cool as a cucumber

[fordem]

Fatzook wrote:

SierraDan wrote:

But don't you turn it off before you drive in?

Thats best practice.

Royce is correct to a point. Problem with relying on the thermo switch to shut the fan off once the motor is submerged is that the fan blades may have already flexed and started munching on you radiator core by then.

Depends on where the fan is mounted - in this case, since he still has the engine driven fan and is adding an auxiliary fan, it'll be in front of the radiator, so any flex will be away from the core.