Wiring Up Fans to a Timed Switch?

[bigcheez2k3]

Like ginge's, my fans aren't coming on either. I've been reading his thread and understanding what I need to do in order to wire them up to a switch.

However, I've had an idea. You know how the rear demister lights up when you press the button and goes off after a certain amount of time, I was thinking of doing this with the fans but not quite sure how I'd go about it.

Is it a case of a different type of relay?

[cully]

when i get home i will look at the details on the demist relay to see whats posible
how long does the demist stay on for?

so you want a complete new system independant of the pug one?

what do you want from below
one fan or two?
temp controlled via water temp?
manual switch overide?
push button timer override?
run with ign on only or off?

what car you got i might be able to pick up some of the existing wires?

[bigcheez2k3]

when i get home i will look at the details on the demist relay to see whats posible
how long does the demist stay on for?

so you want a complete new system independant of the pug one?

what do you want from below
one fan or two?
temp controlled via water temp?
manual switch overide?
push button timer override?
run with ign on only or off?

what car you got i might be able to pick up some of the existing wires?

I think the demister is usually on for at least 5 minutes, which is longer than I want the fans to be on for. Ideally one minute at a time as that should be enough to get the temp down.

so you want a complete new system independant of the pug one? Yes as currently my fans aren't coming on when they should be, temp got close to 100 in traffic one morning this week, had to put the interior heater on to cool it. We are going to test them first to see if they are bust though as got a spare set I can swap in.

what do you want from below
one fan or two?
temp controlled via water temp?
manual switch overide?
push button timer override?
run with ign on only or off?

From the above I'd ideally like both fans to come on via a switch I control from the cabin that is on a timed relay so it automatically turns itself off. Not too fussed about ignition on or off as if it's purely controlled by me it will only be used when I want them to come on.

Car is a 'V' HDI with DT engine swap so engine bay loom will be different I think

I have loads of wiring left over from stripping the loom from the old car so I'm assuming that would be ok to use? Got varying thickness's to carry the different powers.

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To add; Have some oem switches like the hazard and demister so planning to use one of those in the hole next to the airbag switch.

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Got a soldering iron and heatgun so just need some heat shrink and I can do it properly. Have pretty much all the connectors left over from my ph2 dt loom too.

[cully]

i would advise against only having manual control human error will kill the car

if it were me i would have auto control with a manual overide be it timmed or just a switch

on your rad have you a blue stat switch or a blanked hole?

[bigcheez2k3]

Looks to be something blank under the top hose on the rad but I think on a dt, the thermostat plug is near the fuel filter where the spring thermostat is. There is a blue plug there.

I agree with what you say, manual override would be a better idea.

[Niall]

I have a relay board in my car that would be ideal for this. It's about £25 delivered but it's very customisable.

[cully]

now to confuse you!

this drawing use's the timer relay and button for the demist

personaly i think its a bit OTT

   


personaly i would ditch the timmer idea

it would be easyer wiring it like this

   

[bigcheez2k3]

Thanks Cully, as you say, the simple switch without timer will be easier. I didn't think one on a timer would add quite that much complexity to it all.

What size relay would be needed? I see it says 25-35a for the fuse so something matching that would be adequate?

[cully]

you could use the original pug green relay or the brown one
as for the timer you could do it easyer but you would have to source non std pug parts
which would be hard to replace if they went faulty