Faulty/Inop Air-Con Pusher Fan...E53 3.0 Diesel 2004

[X5-D-Sport]

Just did a voltage measurement at the power feeds to the fan unit... 13+ volts, live feed engine on & off... same as the rest of the vehicle.

The fan does NOT do a little dance when engine started (as I understand this is a sign of a faulty fan)

In 12 months, the fan has never spun...

I noticed a match-box sized module on top of the rad nearest the fan connector that's spliced into the loom... no idea what it does.

The Air DOES get freezing cold when the vehicle is moving & air is forced thru the front of the vehicle.

I did notice erratic interior temperatures during winter - so wondering if the fan operation also needs some sort of cabin/interior sensor to be working some where ?

Is there a relay that fails ?
Known wiring failures ?
Module failures ?
Cabin Temp sensor some place ?

It's getting hotter now, and would appreciate any help in getting this working please.

Where is the next best place to look to chase this AC fan failure issue ?

[Smeeagain]

have a look at my air con blockage post earlier in the week - folk were mentioning the FSR - you could check that? As it happens mine wasn't FSR it was only needing re-gassing but there may be useful replies

Smee

[X5Sport]

Is this the module?  According to RealOEM is is an F.AUC sensor - which is not exactly a simpke explanation and no location given but the size might be right?

EDIT: it's the auto recirculate sensor apparently - or 'stink sensor' that shuts the flaps to keep noxious gases controlled and out of the cabin in a tunnel.

[X5-D-Sport]

Ahhh yes... that is the module..

That wont affect the pusher fan I guess...

[X5-D-Sport]

Re SMEE's FSR... the interior blowers are fine... its the front Radiator pusher fan that wont power up.

[X5Sport]

The three wires on the connector are +12v, control and chassis.  A pulsed signal comes down the 'control' and that determines the fan speed.  That data appears to come from the AC module in the car.

If everything else is working - and it sounds that it is once the car is in motion - then the actual fan has in all likelihood died.  It appears to be a common fault.  If it 'twitches' but nothing else happens after 5 secs then it's dead.  If it hasn't started after a minute then the likelihood increases.

From what I am reading on various threads, the fan should be running if the a/c and engine is running.  Its job is to keep the condenser cool all the time.  If the fan doesn't start with the a/c set to its maximum internal fan speed and minimum temps then the fan itself must the the suspect.  A BMW Dealer, or anyone with a GT1 tester kit (copy of the dealer system) should be able to see a fault code as a failed fan will show up.

New ones are not cheap so a car breaker may your best bet.  It also seems that to change it you need to remove the front bumper.... :wall: :rant:

[X5-D-Sport]

MMMM

I was afraid of the front Bumper removal bit ...    :'(

[X5Sport]

Have you tried a scanner 1.4 on it?  Don't know if you have one or someone near you has that can help.

[X5-D-Sport]

I've managed to get a fan motor unit on its own, and also with a little modified tool I can fit it WITHOUT removing the whole front-end/bumper of the car.  The knackered unit is off the car awaiting the replacement from e-bay next week - we will see if it fixes the issue.

[X5Sport]

Fingers, toes etc crossed 

[X5-D-Sport]

I've learned NOT to get toooooo hopeful or excited - it's a BMW after all lol...

And we are still suffering for winning WW11.... the Axis-Forces have found their revenge in the form of BMW cars and still managed to dominate the world, when the punishment via Panzers & Blitzkrieg ceased..

However - love this car even so lol

[X5-D-Sport]

Update on AC Pusher fan failure.

The fan has never worked the whole time I've owned this vehicle

Voltage & power IS reaching the fan at the big connector nr the fan.

Expected the fan to be a failed unit, so connected a fan that was a know working unit to the wiring connector - that does not work either when the engine is running & the snow-flake button is illuminated and switched on..

all the fuses are OK, power to the connector, substitute fan also won't power up..

So, its safe to presume that the fan is OK, but is not getting a signal to operate thru the thing wire......

Any suggestions as to where look next ?

[X5Sport]

Get a fault code read done.  It might tell you where to look next.

I'm assuming that when you press the snowflake button with the engine running you can hear the AC compressor clutch operating?

[X5-D-Sport]

Yep, the clutch kicks in & out....

The AC operates fine when driving forwards, & air is going thru the Rad/Exchanger.
When you switch it on & off it works & shuts down when switched off...

Just cannot get the fan to work at all !

[X5Sport]

Hmmm.

Methinks the pulse train is absent so the fan speed controller is not getting the necessary signal.

If you had access to an oscilloscope you could see if the signal is present.  If it isn't then the only option is to trace the wires back, or follow them on a wiring diagram.

If you can get the AC controller out from the dash then you might see the same wire colour codes as the fan plug coming to another connector.  You could do a continuity check to see if they are all intact.  If they are and there is no other component in circuit it points to the AC controller itself.

No one else on here seems to know how the system works so I'm stuck not knowing what feeds the signal to the fan speed controller and what components lie between the AC on button and the fan itself?