Manual Over-ride Switch For Rad Fan

[DanS1982 0]

I've searched but I need somthing clarifying.....

 

I'm about to wire a manual override switch for the rad fan whilst keeping the oringal thermoswitch on the car so the fan still cuts in on its own when hot.

 

I want to simply wire in a direct feed from the battery to the fan (via a fuse, relay and switch). Is this ok to do? Will this cause problems when the car reaches the temp the fan normaly cuts in on as it will then have two sources of 12v running to it if the manual override switch is turned on at the same time.

 

Any help/advice appearciated.

 

Dan

[Richie-Van-GTi 73 2 Cars]

should be fine as it wont actually have 2 12v sources, it will only get 14v max as thats all the battery is.

[Emmy Seize 8]

I want to simply wire in a direct feed from the battery to the fan (via a fuse, relay and switch). Is this ok to do?

 

Yes, certainly.

 

But why do you want to install a second feed anyway?

 

For an override, all you need is a switch and a length of wire.

 

Just wire the switch in parallel to the thermoswitch into the existing loom.

 

No need to worry about relais and fuses then.

[Spiky 37]

Yes, certainly.

 

But why do you want to install a second feed anyway?

 

For an override, all you need is a switch and a length of wire.

 

Just wire the switch in parallel to the thermoswitch into the existing loom.

 

No need to worry about relais and fuses then.

 

 

 

thats what i plan to do, simplest and easiest way

 

 

Dan hi assuming the same same DanS i know

[tom_m 0]

thats what i plan to do, simplest and easiest way

Dan hi assuming the same same DanS i know

 

yup thats what i've done, just make sure you use high enough rated cable. the fans pull quite a bit of current. if you use too small a gauge the current will melt it and cause a fire.

[DanS1982 0]

thats what i plan to do, simplest and easiest way

Dan hi assuming the same same DanS i know

 

Yes mate it is

 

Locating the thermoswitch looks alot harder just tapping into the positive of the fan so I thought I'd do that. I already have a power source next to my switch (battery cut off) so there will be no extra wiring run from the battery.

 

Also how is the thermoswitch triggered? Surely running a switch in parralel with the high speed circuit for the fan will still only operate once the thermstate has been triggered? i.e. the fan wont run from cold?? Is it on the right or left of the rad by the way?

 

cheers,

Dan

[tom_m 0]

Yes mate it is

 

Locating the thermoswitch looks alot harder just tapping into the positive of the fan so I thought I'd do that. I already have a power source next to my switch (battery cut off) so there will be no extra wiring run from the battery.

 

Also how is the thermoswitch triggered? Surely running a switch in parralel with the high speed circuit for the fan will still only operate once the thermstate has been triggered? i.e. the fan wont run from cold?? Is it on the right or left of the rad by the way?

 

cheers,

Dan

 

the rad fan switch is located on the passenger side of the rad at the top, near the top hose.

 

by wiring the switch in paralell to the existing switch you are bypassing it, either switch can switch the fan on, but both must be off for the fan to be off.

[Paul T 0]

The wiring to bypass the temperature switch was already fitted on my car. I was told it was for testing the fan operation.

Follow the wires back from the temp switch, after a few inches they split off and end in an empty plug, on mine behind the headlamp. If you short the plug connections the fan should run. Do it via a switch mounted in the dash - job done.

Don't need to bother with relays, fuses etc as it just uses the original fused supply.

Only down side is if the fan fuse blows you don't have a seperate supply, but if a faulty fan has caused the fuse to fail, switching to a seperate fused supply will just blow that fuse.

[jonah 1]

Yep, as everyone else says, just wire a switch in parallel with the thermoswitch. And if you get a 3-position switch (on-off-on), then you can have a dual speed override for no extra effort! I have done this and it works perfectly, I posted step-by-step instructions on here a while ago so do a search.

 

The spare plug that Paul T mentions is for Peugeot diagnostics I assume, but the wires going to it are really thin, so I wouldn't want to use them. Best to tap directly into the thicker wires.

[DanS1982 0]

Yep, as everyone else says, just wire a switch in parallel with the thermoswitch. And if you get a 3-position switch (on-off-on), then you can have a dual speed override for no extra effort! I have done this and it works perfectly, I posted step-by-step instructions on here a while ago so do a search.

 

The spare plug that Paul T mentions is for Peugeot diagnostics I assume, but the wires going to it are really thin, so I wouldn't want to use them. Best to tap directly into the thicker wires.

 

Jonah, I have read your instructions and it sounds simple enough but I still dont understand how fitting a switch in parallel to (for example) the high speed pin on the thermswitch will turn the fan on and off? What stops the fan from coming on before fitting the switch? how is the different speeds activated?

 

Cheers,

Dan

[jonah 1]

The standard thermoswitch contains two switches that come on at different temperatures. The higher temp one connects the fan directly to the battery for high speed, and the lower temp one connects it via a resistor (mounted somewhere near the radiator) to run the motor slower. If you connect switches in parallel, then the circuit will operate whenever either (or both) of the switches are closed. I don't really understand your question unless you're confusing parallel connections with series connections...

 

The switch you need has 3 terminals, these connect directly to the 3 terminals on the thermoswitch. I can't remember which colour wire goes to which terminal but it won't damage anything if they're the wrong way around, so just try the different combinations until one of them gives you the dual speed control.

[DanS1982 0]

parallel connections with series connections...

 

Sorry for being dumb, but can you give an example? Parallel means in-line to me?

Edited January 11, 2007 by DanS1982

[crogthomas 0]

Parallel means next to each other, i.e. parallel to each other.

Series means in-line, i.e. one after the other in series.

 

I will refrain from taking of any piss, or mentioning dictionarys, or even the internet, that would be too easy.

[Ben_M 1]

I did all of this to my 205 when i frist got the car as it was running really hot. I installed the second fan and wired in two switchs into the dash. One switch in to operate the fans in the low speed mode (through the resister) and the other was the high speed mode ( which was a direct feed to the fan ) .. But to tell you the truth at the moment i cant remember how i did this, It was 6 years ago ! < ill try to have a look today and see if a can trace the wires, to write up a plan , ill try for some photos aswell

[DanS1982 0]

Parallel means next to each other, i.e. parallel to each other.

Series means in-line, i.e. one after the other in series.

 

I will refrain from taking of any piss, or mentioning dictionarys, or even the internet, that would be too easy.

 

Thanks, being a qualified civil engineer I understand what the word means.

 

And thanks to a friend on another forum I understand what to do now, explanations are obviously far to much to ask for on here

[Spiky 37]

i was glad to help