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AU Fan - a better way to wire

30K views 40 replies 14 participants last post by  NoBByxr8 
#1 ·
There have already been a few AU fan installations detailed on this forum. The installation of the fans has usually been performed very well, but the electrical side has left a lot to be desired.

Knowing that none of the previous installations were to my standard, we knew that we would have to do some research.

The first thing was to find out how Ford wired up the AU fan on the AU falcons. Below is the circuit diagram.


http://www.fordforums.com/attachment.php?attachmentid=32983&stc=1



The PCM allows three options. The first is for no signal and no fans. The second involves a signal from EDF1, which runs the fans in series at low speed. The third involves a signal from EDF2, which runs the fans in parallel at high speed.

The next thing that we needed was some switches to do the job of EDF1 & EDF2. Before I could decide on the appropriate temperature for the switches we had to decide where we were going to locate the switches.

We chose to locate the switches at the exit point of the radiator. The reasons for this location were twofold. The first was that we didn’t want the switches to ever become exposed due to a loss of water from the radiator. The second was that we wanted to control the temperature of the water leaving the radiator. Switching at the thermostat or radiator inlet gives you little control of the temperature of the water leaving the radiator.


Next to decide was the style of switch. We quickly decided on the type that screws into the radiator. These are used by many car manufacturers such as Ford, Mitsubishi, Nissan etc. This decision was made easier by my past experiences with capillary switches and the $2 thermal switches.


Deciding upon suitable switching points was the next step. I run a 180 degree Fahrenheit thermostat, so the points had to be compatible with that. To choose the switching temperatures I chose to copy the automotive industry. Most cars running 193 degree Fahrenheit thermostats, so I was looking for a switching points around 13 deg. F lower.


Searching through electrical automotive catalogues, we managed to find a dual switch that fitted the bill.
It’s properties were:

Make: Tridon
Part number: 2FS 214
Low temperature switching points: On 80 off 75 deg. C
High temperature switching points: On 87 off 82 deg. C
Thread: M22 x 1.5
RRP: $140 (far less for trade)


Below is the switch installed in the radiator:

http://www.fordforums.com/attachment.php?attachmentid=32981&stc=1


The next step involved deciding upon the wiring. Obviously the wiring was to be based upon the factory setup, but using temperature switches instead of a computer. There was also some other features that we wished to include. Some people have reported that they have had trouble starting their cars when the fans were running. Therefore we wanted the fans to stop when the engine is cranking. This can easily be achieved by running a wire from the “start” terminal of the ignition to a normally open relay. We also wanted the fans to not run when the key is in the “off” position. This will eliminate the risk of the fan unexpectantly starting when working on the car. If the car is hot when you shut the motor down, you can easily leave the ignition in the “accessories” position allowing the fan to run.

Below is the wiring diagram that we came up with:


http://www.fordforums.com/attachment.php?attachmentid=32980&stc=1


For the relays, we chose to use a solenoid block like those that Ford used. Below is a picture of the installed relays:


http://www.fordforums.com/attachment.php?attachmentid=32982&stc=1




We hope you have found this information useful.

XBGS351 & SILICON
 

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#2 ·
Thanks Just what I was looking into!
Where does this Tridon temp swicth sensor fit? I have a wider XC radiator.
Where would I find a M22 x 1.5 thread in the radiator?
Do you have a link to 2FS 214 stat?
I have the EF fans which have one single speed and one dual speed 3 wire motor so I dont thing the schematic will help.
But, Thanks again
 
#4 ·
Where in the radiator is the switch mounted and how is it mounted into the radiator?

Why does that battery only have one pissy little wire coming from the positive terminal? That's all I could make out in the pic anyway.
 
#6 · (Edited)
shaynet said:
Where in the radiator is the switch mounted and how is it mounted into the radiator?

The adapter is a M22x1.5 nut that has been put in a lathe and had a step machined into it. The radiator has had a hole put in it and the area around it pulled out flat so the modified nut sits properly in it (step on nut fits into hole). The nut is then soldered in; this is easy with a propane torch/solder/baker's soldering fluid. Just take it easy on the heat application.

Why does that battery only have one pissy little wire coming from the positive terminal? That's all I could make out in the pic anyway.

All of the positive leads come off the remote starter solonoid under the battery tray, the thin red wire to the MSD is the only exception. You can just make out the heavy positive lead coming of the terminal to the solonoid as well.
 

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#9 ·
xbgs351 said:
Your a braver man than I.

I had my setup switched manually on a 3 way switch, up= both fans on, down = 1 only on and centre = off.....

I have now changed slightly as I did not want to take any chance of cooking the motor, I've added a inline thermal switch that turns on 1 fan at 200deg F and turns off again at 185deg F, this works well and I can also manually override the fans if I wish. As I have a 170deg F thermostat it suits me. My car sits on 180-190 while cruzing and I've never really need to have both fans running. Even in heavy traffic the auto fan holds the temp at 200 and goes no higher !! I've also switched the auto fan to the ignition so it does not keep running when I turn the car off, I reckon on a hot day the fan could keep going for 20mins or so before it cut off, that would kill the battery in no time at all.
 
#10 ·
I've got a thermal switch from VPW and have both fans wired to turn on at once automatically at high speed. Works a treat, and I only ever notice I have thermos when idleing. Care-free cooling at it's best and dead easy to wire up. Won't run unless key is turned to "on" also.
 
#12 ·
Update

The AU fan has been installed on my car for a while now and it has worked perfectly on the street. Two weekends ago I spent the day driving at Winton and a couple of problems became evident.

The first problem is that when you are continously driving very hard, the temperature of the water exiting the radiator must be considerably cooler to keep the engine from running hotter than desired. So when circuit racing the fans must be continously running at high speed.

The second problem was that even with the fans running at high speed the motor was still getting hot after doing 3 to 4 hard laps. It is apparent that every effort must be made to seal the edge of the shroud against the radiator. I will do this by plastic welding strips of plastic in the appropriate gaps.
 
#13 ·
Re: Update

xbgs351 said:
It is apparent that every effort must be made to seal the edge of the shroud against the radiator. I will do this by plastic welding strips of plastic in the appropriate gaps.
Yep, small though those gaps are, I'm sure HEAPS of air get sucked in there instead of thru the radiator core. I'll be welding mine up too.

Are you running standard thickness radiator?

The fat ones that hold twice the volume of water would have to help in your application.
 
#14 ·
Re: Update

TruBlu351 said:
Yep, small though those gaps are, I'm sure HEAPS of air get sucked in there instead of thru the radiator core. I'll be welding mine up too.

Are you running standard thickness radiator?

The fat ones that hold twice the volume of water would have to help in your application.
It's a standard width and core radiator.
 
#16 ·
zed54 said:
I am in the process of installing AU twin thermals in my XE.
I have chosen to upgrade the alternator at the same time. If I replace my existing alternator with an 80A or 120A, what cables do I need to upgrade to suit the new alternator?

Thanks
Joe
the alt charge wires is where you should start
 
#17 ·
zed54 said:
I am in the process of installing AU twin thermals in my XE.
I have chosen to upgrade the alternator at the same time. If I replace my existing alternator with an 80A or 120A, what cables do I need to upgrade to suit the new alternator?

Thanks
Joe

good idea, I would choose what ALT first and then go on the wires from there.
I got a Bosch Alternator 85A BXU1285A $180 from repco...

its listed as a multi-fit or vt commodore alt. was easy to install, just needed to get a different spacer made up..
 
#19 ·
brenx said:
Or just swap the front half of the Ford alternator onto it like I did ;)
What about gearing down the pulley to slow the revs of the alt so it doesn't disintergrate at 7000 + revs?

Someone told me to go to the hardware store and get a washing machine pulley and then have it machined to fit.

Anyone got a fix to install a slightly larger pulley to slow it down?

What size charge wire do you need for a 85 amp alternator?
 
#20 ·
shaynet said:
What about gearing down the pulley to slow the revs of the alt so it doesn't disintergrate at 7000 + revs?

Someone told me to go to the hardware store and get a washing machine pulley and then have it machined to fit.

Anyone got a fix to install a slightly larger pulley to slow it down?

What size charge wire do you need for a 85 amp alternator?
My 85amp one cam with a pulley that was larger than the old Ford one.

Buy the wire from an auto elec as it'll have to have some fusable link in it. Autoelec should be cheaper than buying it from Autobarn or the likes ;)
 
#21 ·
zed54 said:
I am in the process of installing AU twin thermals in my XE.
I have chosen to upgrade the alternator at the same time. If I replace my existing alternator with an 80A or 120A, what cables do I need to upgrade to suit the new alternator?

Thanks
Joe
Why are you looking at upgrading your alternator? These fans only pull around 10 Amp when on high speed and they hardly ever run at high speed. The reason for the 30 Amp Circuit breaker is that the fans momentarily draw around 17 Amps when starting.

Recently when I was at Winton, I destroyed my alternator at about 10am. The fan was running nearly none stop at full speed until around 4 pm, when the battery finally ran out of oomph.

My replacement alternator is a 40 Amp alternator pulled off an XY.

If you are still going to replace your alternator you will probably be getting an internally regulated alternator. The only wire that may need upgrading is the wire running from the positive terminal of your battery to the threaded terminal on the alternator.
 
#22 ·
40amp alternators not enough if there is any other electrics in the car. I'll had the high speed side of the fans fill two 30amp relays. Completely cooked/melted them due to heat generated from being on only during waiting in the staging lanes @ Heathcote. The 40amp ones given me no trouble.

Due to running a 40amp alternator and thermo's I got stuck in a service station because I was sitting in traffic for 40mins and the fans drained my battery.

In my experience 85amp is the bare minimum. My battery is now almost completely stuffed due to being drained dead flat all the time by the fans from when I had the 40amp alt.
 
#24 ·
65A alternator and havn't had a problem. That's even with the stereo up, lights, wipers, all on at once. I'd still say bigger is better though!
 
#25 ·
pracy said:
good idea, I would choose what ALT first and then go on the wires from there.
I got a Bosch Alternator 85A BXU1285A $180 from repco...

its listed as a multi-fit or vt commodore alt. was easy to install, just needed to get a different spacer made up..
Mine fitted straight out of the box but I had to grind the bracket a little and run a shorter belt.
 
#26 ·
ALTERNATOR

I tested the battery voltages on my XB under various conditions to see if the 40 Amp alternator would be sufficient for an AU fan setup. Following are the results:

1. Car off, no accessories running.
= 12.8 Volts

2. Car running, including MSD6AL, Holley Blue and interior light.
= 14.0 Volts

3. Running, with fan on low
= 13.6 Volts

4. Running, with fan on high
= 13.4 Volts

5. Running, with fan on high and low beams on.
= 13.2 Volts

6. Running, with fan on high and high beams on.
= 12.2 Volts

I have never found myself stuck in traffic on a very hot day with my high beams on, so I am not too concerned about running a 40 Amp alternator.
 
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