E53 X5 Auxiliary Fan test?
 

Hello all!

My AC blows cold at highway speeds but slowly warms up if sitting still for too long. The compressor is functioning, and I have checked pressure on the low-side and it's reading as full. What I have noticed is that the aux fan is not coming on AT ALL. Is there a way to test the AUX fan while it is in the vehicle? I only have a basic scan tool and multi-meter - I do NOT have a tool that can trigger component operation.

Thank you!!

2006 X5 3.0 Auto

What happens when you run the car with the AC off? On other models, when you turn the AC on, the auxiiary fan kicks on.

A couple other things - although the fact it does not come on with AC is one sign the fan is bad.

1 Unplug the coolant temp sensor with car running. It should cause the fan to run.

2. Unlock the cluster sub-menu (read up on it) and enable test 7 to show coolant temps. Once temps hit 100C at idle the fan should come on. Don't let it go over 100C


I just replaced my aux fan in my '05 3.0..it was dead which I confirmed with INPA.

I went with the TYC brand (Taiwan) off amazon. Decent reviews.

The auxiliary fan does not kick on regardless of the status of the AC or the temperature of the vehicle - it's just dead all the time. What I'm trying to discern is whether or not the fan is actually bad of perhaps if a sensor is bad and it's not calling for the fan to kick on. I don't know if that would be a temp sensor or something else, but for now just trying to determine if the fan itself is functioning.

Awesome - Thank you both!! I'm going to run through the diag tomorrow. I found the fan online - $180 delivered with new fan shroud clips.

here's a suggestion
 

Here's a suggestion from an older thread I found: post # 56 from the thread "How to test if Auxiliary fan is bad?"https://xoutpost.com/bmw-sav-forums/...ml#post1101833
but never tried (my aux fan wasn't plugged in after I had taken out the shroud after my electric fan conversion). I looked for the A/C connection, and found where I had pulled the aux fan plug loose, instead. There was no problem.

When replacing the fan, get a brushless fan. I have a brushless aftermarket fan on my X5. It takes over 10 seconds for it to stop spinning once power is off. You can hear it spin up too.

Had the same issue as topic starter. Replaced the fan, and now ac blows cold also while standstill.

The other option is to buy the fan....make sure it is fully returnable...then lay it on top of your radiator shroud, plug it in, and turn the AC on...

If the fan does not spin, you have some other problem.

I thought of this, but I think I had trouble finding a fully returnable fan..even on Amazon.

Based on online reports, I happen to think the aux fan crap out on an E53's more frequently than on E39 or E46..which seem to last the life of the car....maybe yet another example of inferior parts supplied to US-made cars like E53. I can't complain too much though, 15yrs for a fan is not bad.

Good call on the returnable fan. And yes, 15 yrs isn't bad for a fan. We're also at 225,000 on the X5 so I really can't fault the car for many of the issues I've ran into. I owned a Toyota Sequoia for 260,000 before this however and the comparison is what gets me into trouble - it's like apples and oranges (if one of those pieces of fruit is more attractive and handles better lol). That being said, my first BMW was an E30 that I sold with 340,000 - that's what got me into Bimmer's in the first place. This is my sixth...

1987 325 coupe MT
2001 540i M Sport AT
2005 X3 M Sport MT
2002 325ci AT (for my son)
2006 X5 3.0 AT
2002 X5 3.0 AT (for my son)

Thanks! Any recommendation on where to find one?

Topaz makes a brushless aux fan. I think they are still available on Amazon.

OK - per Effduration:

1) Unplugged the temp sensor on the lower radiator hose. Fan did NOT kick on.
2) Found the sub-menu, option 7, pushed to 100C. Fan did NOT kick on. Ran the car after to cool it down and found that at highway speeds it drops to about 89C @ 40mph+

Per WorkingOnIt thread:

1) Unplugged the A/C high pressure sensor. Fan did NOT kick on.
2)Wiring plug IS plugged in and I verified that it IS getting 12 volts.

Based on this, I think it's the fan. Going to order a returnable unit just in case (unless somebody else kicks in another thought?)

Thank you sirs!

Did you have any trouble with the car accepting this part? I read some Amazon reviews about how the the brushless fan wouldn't assimilate with the PCM and required a reset? thanks in advance.

I think you might mean with the DME (main computer) and not PCM. You'll need to clear the codes in your DME to ensure it checks for the "start up" sequence after you install the fan. If you're unsure, I would recommend you put the fan on top of your engine, connect it to the wiring harness, clear the code and then either start the car and set the AC to on....or if you have INPA or other tool you can activate the fan to check it before you take off the bumper cover and the like.

So far this hasn't tripped any codes whatsoever, so there is nothing to clear... I have a basic, Harbor Freight scan tool - which I know I need something different. Am I going to have an issue? Can I somehow clear any other codes via the cluster sub-menu perhaps?

If the fan has in fact failed, there will be a BMW-specific error code in the DME - this code may need to be cleared before the new fan will work. You'll need BMW software tools (or a Foxwell etc.) to clear this code.

My fan failed in my ‘06 3.0, and I had no codes.

I have Peake, INPA other BMW-specific code readers

It SHOULD throw a code for fan failure, but it doesn’t always do so.

Same here. '01 fan failed, no codes as read by my foxwell.

Sorry to raise an old thread but my ac fan is dead. Got a replacement which only runs if unplug the ac sensor on the aluminium pipe. What could be my cause. Obviously more than just the fan was bad

You might be low on refrigerant, take it to a reputable shop and have it checked.

Thanks. I should add my ac blows cold even without that fan running. Dies that make a difference to your recommendation?

Most of the ac places round here, Cleckheaton West Yorkshire I'm not sure are that reputable?

I'm guessing by A/C fan you mean the aux fan. It would help if you included some more information on the vehicle you are working on and maybe the reason you replaced the fan and what kind of fan you replaced it with etc. Maybe try checking/clearing any codes like mentioned in this thread.

There aux fan only runs as needed. The AC won't run at all if the fan fails the startup test. A bidirectional scanner will run the fan at various speeds to test proper operation.

Usually aux fan will turn on as something like 220F if AC is off and 180-200f when ac is on but that's just a generic example. I don't know the rules at all for e53. I do know that I've gone months without the fan kicking on then weeks where It kicks on every day.

E53 has the mechanical fan and the aux only needed to suppliment when that's not enough airflow (eg stuck in traffic and hot out)

Haha I thought they were in the middle of a heat wave over there but London is only 20 C so saying the A/C blows cold doesn't mean much.