Relays .. One for the Auto spark in us

[mike 90 RR]

I've installed thermo fans off a NL Ford and got all the high / low relays gear from the Ford while I was at it :)

I have 2 inputs ... being

1: Aircon compressor clutch feed for the "low fan side"
2: Temperature feed for the "High fan side"

http://img200.imageshack.us/img200/9828/fancircuit.jpg

The 3 relay's in a row, up the top, are the original Ford relay's that control / feed the high or low speeds of the fans

The relay that feeds from the Aircon works fine :)
The relay that bridges power across high to low gets stuck ON :(

When you activate the aircon ... the low fan speed works (as it should) ... The Temp switch activates ... the relay in the middle, & bridges across to the low side .. & gives me HIGH fan speed (as it should)

The problem is that when the Temp switch turns OFF ... the relay in the middle (that bridges) is stuck ON .... to return to Low speed and get that bridging relay to break OFF ... I have to switch the aircon OFF / ON (for a split second) to release the bridging relay & then it return's back to Low speed

I have put a multi meter on it (bridging relay) and found that it spiked 3v with a drop to 1/2 volt constantly ... (measured on the input + line feed of the temp input wire) ... Basically the coil is "making volts" because of the current of volts passing thru it

All the relays are those standard types that you can buy over the counter
(The 3 relays in a row are the original ford issued)



IS there a more agricultural style relay I can use?? ... as this one is too trigger happy for this application


(& Yes ... I have manually tested all the fan speeds first & the way it works ... before I installed the relays)


Mike
;)

[THE BOOGER]

An agricultural fix would be to only use two relays one for low speed fan feed by ac clutch and one for high speed fan feed by your temp feed same result but much simpler:)

[mike 90 RR]

An agricultural fix would be to only use two relays one for low speed fan feed by ac clutch and one for high speed fan feed by your temp feed same result but much simpler:)

Good suggestion ... BUT ... I can't alter the 3 Ford relay setup ... as that is how Ford have set them up for the fans ... My diagram (Slightly) glosses over how they work .... as I think the low side feed relay, has a resisted feed wire ... but shows it's basic functions of how Ford set them up



I can only alter the AC & Temp input switch relays ;)

Mike

[BigJon]

I was under the impression that they ran the fans in series for low speed and parrallel for high speed... but I could be wrong.

[slug_burner]

The description of what is happening and the diagram don't gell for me.

That middle relay (blue one below the three red ones); all it is doing is making the circuit go into a don't care what the aircon switch is doing state. Once the Temp Switch powers that middle relay up you can turn the aircon switch off and the low speed feed of the fans will still be energised.

I suspect that the fans have two windings and to run at high speed they need both the low speed and the second windings to be energised to produce high speed. That middle relay just means that when you have hit the temp switch threshold it does not matter if you turn the aircon switch off the fans will run at high speed until the temp switch senses the temp to be below the ON threshold.

I can't see how the middle relay would latch ON, once the temp switch goes to OFF the middle relay should deenergise.

There must be some other wiring that is not shown on the diagram to explain the described behaviour.

[mike 90 RR]

I can't see how the middle relay would latch ON, once the temp switch goes to OFF the middle relay should deenergise.

Neither can I ;) .... but here we are :angel:


Mike

[Sprint]

try asking on Australian Ford Forums - powered by vBulletin (http://www.fordforums.com.au) , theres been more than a few people on there who have put the EF/EL/AU thermo fans into earlier falcons

[mike 90 RR]

I have put a multi meter on it (bridging relay) and found that it spiked 3v with a drop to 1/2 volt constantly ... (measured on the input + line feed of the temp input wire) ... Basically the coil is "making volts" because of the current of volts passing thru it

IS there a more agricultural style relay I can use?? ... as this one is too trigger happy for this application


I can't work out how it's making volts .... IE energising ...

I recon it could all be solved with a more agricultural style relay ... So what kind of relay would suit??? :angel:


I was under the impression that they ran the fans in series for low speed and parrallel for high speed... but I could be wrong.

I recon your right :)


try asking on Australian Ford Forums - powered by vBulletin (http://www.fordforums.com.au) , theres been more than a few people on there who have put the EF/EL/AU thermo fans into earlier falcons

I was hoping that it wasn't gonna be that complicated :eek:

Mike
:confused:

[fraser130]

It might be the time of day, but I think if you take out the blue relay in the middle it will work?
Can I ask why you have the aircon relay operating another relay, would it not be better to operate the low directly from the aircon relay?
I think the coil in the centre relay is providing enough voltage from the low relay output to keep the other relays energised.
I still can't see why the centre blue relay is there.
Fraser

[Rangier Rover]

Hi Mike,
Try a Relay with a built in resistor. What you are experiencing there is a common problem with non resistor relays when you start stacking them up like that.

Tony

[mike 90 RR]

Can I ask why you have the aircon relay operating another relay, would it not be better to operate the low directly from the aircon relay?

I still can't see why the centre blue relay is there.
Fraser
Thanking you for your thoughts :)

The 3 in a row relays are fixed / can't change em ..... only the 2 at the bottom are what I want to add to control the direction of the 12v

If i didn't have the A/C relay ... then 12v would be sent back up to the A/C itself .... Basically the relay is to isolate the A/C power source and keep the feed direction towards the fans / relays

The same for the center blue relay ....

Mike

[mike 90 RR]

Hi Mike,
Try a Relay with a built in resistor. What you are experiencing there is a common problem with non resistor relays when you start stacking them up like that.

Tony

Ta for that Tony .... was hoping for some "Yea / seen that before" :D

All the wholesalers would say is ... "mate we sell em / don't know what they do, but we got stacks of em"

All my relays have diodes in them ....

Mike
:)

[slug_burner]

With mechanical switches the diodes probably don't matter. With transistors you need the diode to stop the voltage spike when you stop the drive to the coil, otherwise you end up puncturing the drive transistor.

[Rangier Rover]

Ta for that Tony .... was hoping for some "Yea / seen that before" :D

All the wholesalers would say is ... "mate we sell em / don't know what they do, but we got stacks of em"

All my relays have diodes in them ....

Mike
:)
As you know the diodes will only allow power to pass one way but have little resistance in the forward polarity.
Just thinking.... If you can't come up with a relay with resistor just wire in a small globe (2 to 5w) from the earth to the switching pole and see if the problem goes away.

There you go.... If it works just another hole to drill in all that plastic for another thingy:p

Tony

[rovercare]

You still have the original condensor fans yea? if so, junk the relay setup, as you don;t need the AC input, the way they achieve low speed high speed is either operating them in series/paralell, basically junk the lot, use 2 relays to control the fans with you thermatic switch and your done, makes the whole lot simple and easy to fault find, plus if one fan craps its knickers, it don;t effect the other

I've wired more than one set off falcon fans, in both retaining the original control, for falcon engine conversions and just utilising the fans for others

[mike 90 RR]

You still have the original condensor fans yea?

I was gonna remove them so I get a clean air flow (no obstructions) to the radiator ... Just use the High / low setup on the Ford thermo fans .....

Mike

[mike 90 RR]

Just thinking.... If you can't come up with a relay with resistor just wire in a small globe (2 to 5w) from the earth to the switching pole and see if the problem goes away.

But that means I will have to lift the bonnet every time, to see if the light is on, to let me know which fans working :confused:
:p



Hi Mike,
Try a Relay with a built in resistor.


Fitted them up on the weekend // bought resistor relays .... Top Stuff ... all works now /// like a charm :D

[Rangier Rover]

But that means I will have to lift the bonnet every time, to see if the light is on, to let me know which fans working :confused:
:p




Fitted them up on the weekend // bought resistor relays .... Top Stuff ... all works now /// like a charm :D

Great stuff:D I've done a few here the same way with success as well:cool: