Cabin fan has only one speed - MAX

[OzzieNorm]

Hi Folks.
I have a 2006 ST 3.0TD auto with 92K that has spent its life to date on top of a coal mine. Dust everywhere!!! Every day.

The cabin fan has just one speed - '4'.

Turn it to 0-1-2-3 and nothing happens. Quite.

Why might that be so?

How do I remove that piece of the dash assembly to clean and check the fan switch?

Thanks

[Bulbous]

There's some sort of dropping resistor, just behind the Glove box, I believe. This is exactly what happens when the resistor burns out.
Maybe somebody else has a few more details and can actually help you

[Bulbous]

Look under the glove box you will see a black fan motor (it's up against the kick panel), it should have two wires going to it a blue with a red trace and a blue with a white trace.

If you turn ignition on and with one end of your multi-meter/test light earthed you should have power in the blue with a red trace wire. If you do then you know the fuses are OK.

Unplug the connector from the interior fan motor. With your meter/test light connect one end to the blue with a red trace wire and the other end of your test light to the blue with a white trace wire.

With ignition on run through all fan speeds by turning the interior fan speed switch from 1 to 4. Does the meter/test light give a reading on all 4 settings? If it does then the fan speed resistor is OK and the problem is with your fan motor.

The fan motor can be removed by undoing the 3 screws, you may also need to remove the glovebox (about 6 screws) to get the motor out.

[OzzieNorm]

Hi Steve.
Thanks for your prompt input. Serious good and detailed advice (which I can readily follow).

Will finish my big Aussie Day breaky, then grab my circuit tester and multimeter, and go check it out.

[Having the fan on MAX is great for super hot days - but the A/c can get a chilly as night gets darker. ;o} ]

[Yendor]

I agree with Bulbous, you problem is more likely a faulty fan resistor then a switch problem.

In the photo you can see the black fan motor (LHS of photo) it mounts into the white plastic, just to the right of the fan motor you can see the brown plug for the fan resistor.

You will also need to remove the interior fan and check that it spins freely by hand as this could be that reason the resistor has burnt out.

[Robo]

As a rule of thumb 12v motors change speed depending on power, voltage supplied to them, so if the fan is working then its stands to reason it's not the cause for positions 1-3 not working.
regulation of power is the probable cause, not the fan.
Good luck

[Yendor]

You need to be careful, a blown interior fan resistor could be just the symptom.

The cause could be the interior fan is drawing excess current and has burnt the resistor out, (fan speed 4 does not run via the resistor).

Take the extra couple of minutes and remove the interior fan motor and check that it spins freely before fitting the new resistor, otherwise you could burn out your new resistor.

Also the resistor needs to be cooled by air from the interior fan, so don't run the interior fan with the motor or resistor not fitted into the box.

[OzzieNorm]

There's some sort of dropping resistor, just behind the Glove box, I believe. This is exactly what happens when the resistor burns out.
Maybe somebody else has a few more details and can actually help you

You were correct. It was the dropping resistor.

Could have procured from eBay for between $67 and $75 plus postage. Gave the dealer a chance. $64 - and no postage. Not everything oneBay is cheap; pays to check around.

[vixim]

I have the identical symptom on my 89 GQ. 0-3 nothing, 4 = flat out (and have to yell to talk with passengers over the fan noise). Will check it out when I get home tonight. Is anyone aware if the componentry is in roughly the same places?

[Yendor]

I have the identical symptom on my 89 GQ. 0-3 nothing, 4 = flat out (and have to yell to talk with passengers over the fan noise). Will check it out when I get home tonight. Is anyone aware if the componentry is in roughly the same places?

Yes the resistor is in the same position on the GQ.

If you can't see it just follow the wire harness from the interior fan motor this will lead you to it.

As per my post above (especially with your noisy interior fan) you will need to remove and inspect the fan motor before replacing the resistor.