This topic is applicable to the 90bhp and 115bhp diesel engines and the 2.3 and 2.8 petrol engines with a build date of May 2001 onwards. The 130 and 150 bhp diesels have no controller instead its handled via the engine ECU with the fan speed controller built into the motor itsel - these diesel models can be identified by having only one big fan and not two.

The fan controller is responsible for turning the fans on/off when required by either the use of the A/C system of as a result of engine temperature. A faulty controller can cause the loss of the fan's entirely or them running continuously after the ignition is switched off, the latter draining the battery if not observed.

The electrical side of the circuit is easy to test so you can diagnose if the controller is faulty or something else is causing it to keep the fans on/off. The controller is identified as Ford Galaxy Relay 419 carrying part number 7M5919506. It's the same as fitted to the Sharan and Alhambra.

Start by locating the controller, it looks like a traditional automotive relay except its longer then normal. Remove the battery cover and look below the auxiliary fuse box. Here you'll see it (Blue arrow) mounted side on and bolted to the same bracket as the fusebox. Remove the 10mm nut securing the bracket (Red arrow) - on some car's it will be possible to slide out, on others remove the two star drive screws holding the fusebox carrier to the bulkhead to aid removal.

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Once accessible we can start to diagnose the electrical side of things. There are two implementations out there and whilst the controller is the same for both the wiring differs significantly.

Radiator Fan Controller Pin-Out for the 90bhp and 115bhp Diesels and the 2.8 Petrol
1 - Switched 12V Supply to Radiator 2 (F105 Supply)
2 - Ground
3 - Switched Ground for Radiator Fan 1 (F104 Supply)
4 - Not Used / Not Shown
5 - Supply, 40Amp from F105
6 - Not Connected
7 - Temp Sensor >102*c 12V Trigger OR "Cooling fan run on invert relay" F10 Supply - A/C Above 16 Bar
8 - Ground
9 - Temp Sensor > 95*c 12V Trigger F10 OR A/C System Running

Radiator Fan Controller Pin-Out for the 2.3 Petrol
1 - Switched 12V Supply to Radiator 2 (F105 Supply)
2 - Ground
3 - Switched Ground for Radiator Fan 1 (F104 Supply)
4 - Not Used / Not Shown
5 - Supply, 40Amp from F105
6 - 12V Supply from Fan Run-On Relay
7 - 12V Trigger from engine ECU
8 - Not Connected
9 - Temp Sensor > 100*c 12V Trigger from engine ECU

Note the main difference is that the engines own ECU get's involved with the control signals for the 2.3 where the other system is more basic. This is only a problem if you are diagnosing the fans being on permanently and the triggers are present during testing as it will require more specialist knowledge to know why the ECU is telling the controller to turn on the fans.

The pin-out above is based on a typical relay base wiring as shown below, NOT on the pin numbers printed on the side of the relay which are VW based numbers!
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Ensure the climate/aircon system is turned off for this bit!

Now we can access the controller we need to wait until either the fans are on when they shouldn't be or off when they should be! Disconnect the controller quickly by depressing the base tab and pulling it from the base - with the wiring base now accessible we want to check for the presence of 12V on either Pins 7 or 9. These are signal wires that tell the controller to power up the fans.

If you are diagnosing the fans staying on when they shouldn't be, we want to check these pins have 0 volts on them. If they do, then the fault is with the controller itself.

If you are diagnosing the fans not being on, then one or both should have 12V present. If they do then again the fault it with the controller or the fan motor.

If a controller fault has been identified as the cause of the fans staying on then repair may be possible. The most likely cause will be the relay contacts fusing as a result of carbon build up. This is turn causes a much smaller surface area making it run hot and subsequently keeping the contacts in the closed position. The good news in that cleaning them is easy, the bad news is that the controller is "potted" meaning its sealed from the weather and not designed to come apart.

Opening the controller will require a hacksaw and re-sealing will require some hot-glue! With it on the bench, use the hacksaw to cut through the surround taking care to go slowly and stop once through - a flat blade screwdriver can then be used to pry the case open fully. Use the legends as a template and cut just above the 3,4 & 9 line:

*Others have noted that it is possible, with patience, to remove the potting compound and slide the case off without cutting it**

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With the case now separated we can see the workings of the controller and also that it's name is a little misleading as its nothing more then a couple of relays ;)

Identify the contact pins and clean them with a piece of emery paper, they should be a shiny colour with little to no black markings on - clean gently but sparingly so as not to remove much of the contact material, remember its only the surface deposits that need to be removed! There are 10 patches in total to clean, identified here:

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It should be fairly obvious when doing the job and the arm can be held down to get to the second contact patches.

Once the contact patches have been cleaned up, check the condition of the circuit board and the soldering for any dry joints or discolouration - reheat them as required:

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Finally, thoroughly clean the mechanisms and casing with a dry small paint brush to remove any of the plastic debris, the case now needs to be secured back together and made watertight. The best method here is to use hot-melt glue and run a THIN bead around the casing before sliding it back together - once cooled a stanley blade can be used to trim the excess and make the job look neat. Avoid using glues that "fume" ie, superglue as the vapour trapped inside the casing will stick to the contact points again!

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Finally, reinstall the controller and test by cycling the ignition.

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