Cooling Fan Fault
 

Notice the last time that I scanned my X with Carsoft 6.5 and BMW Scanner 1.4 I received a fault for a Cooling Fan. Had some time today to investigate it a little more.

Try forcing the fan on by turning on the AC. The AC Compressor never engaged so I took out my AC gauge and connected it to the low and high side ports. The static pressure was 45 psi on both the low side and high side (Compressor not running) so there was refrigerant in the system and enough to turn off the low side of the pressure switch.

Took out the laptop and ran BMW Scanner again to check the HVAC for any trouble code none was found, engage the ac switch and that was highlighted in the program, but the compressor did not engage.

So I'm wondering if the DME is not sending a signal to engage the compressor because of the Cooling Fan fault that is in the DME. Try clearing the fault but it keeps coming back. The fan spin so it is not seized.

Haven't bench tested the fan, but my understanding is that the DME send a grounding frequency signal to the fan which cause the fan to spin and at a speed determine by the frequency. No relay is use in turning this fan on. It has two thick wire which I assume is the + and - wires and a thin wire which is the signal wire.

Anyone have this problem before? Solution?

Update:

So today the weather was actually mild enough to work on the X again. Decided to look more into why the aux fan was throwing up a DTC. Got my test light out, unplugged the fan connector and with the engine running I tested the terminals in the connector. None of the terminals lite up my test light. So I must have a blown fuse. Looked at my Bentley as to where the fuse for the aux fan was located and it right behind the glove box. After washing my hands so that I don't mess up the interior, I removed the glove box and there was the fuse box. Holy moly that a pretty big fuse, I don't think I have one of those in the garage. Proceeded to test the fuse and sure enough the fuse was blown. Check another fuse in the fuse box that was also a 50 amp fuse, but was mounted Horizontally instead of like the other fuses vertically. No power, so I removed the fuse hallelujah it's the spare fuse. Inserted the fuse in place of the blown fuse and went back outside to check the connector with my test light. Another Hallelujah the test light lite up. Should have remember what my dad taught me, fuse don't blow for no reason especially 50 amps fuse, but in my excitement to fix the X that little piece of advice didn't pop into my head. My wife thinks I'm coming down with Alzheimer. Plugged the connectors back together and before I could say Shazam, the genie in the fan came out. Having worked on British cars in my younger days I knew that once the genie left the wire, there was no way to put him back in. So it looks like the next expense will be a new aux fan.


..........................to be continue.

Final Update:

We got AC again. Installed the new fan motor and turn on the AC to see if the fan would run. After about a minute the fan kicked in, but the best news is that the compressor is kicking in so we got AC again. I guess that if the fan is bad the DME prevents the AC from coming on.

Had some time so I decided to open up the old fan and find out why it wouldn't run. Remember my first post that when the genie comes out I knew from past experience that you can never get the genie to go back in, looks like there was a major fire in the genie little house. Germany engineering at it finest, take an old standby like a dc motor and upgrade it with SMD devices combine with pulse signals from the DME to control the speed of the fan and now you know why this fricking fan is 500 bucks plus 4 hours to install.

http://i426.photobucket.com/albums/p...psd8b694a4.jpg

There was a recall on those a while back when they first came out. BMW was telling owners to park their vehicles outside while they figured out a solution. Their reason? So when the car burns down, it won't take your house with it. Pretty sad if you ask me, but glad to see that you were able to tackle this yourself!

http://i426.photobucket.com/albums/p...psd8b694a4.jpg

My wife and kids saw the picture and remark that it looks like a city with a quarter of it burnt to the ground.

Thanks for this post. Very helpful.

Btw, do you have diy instructions on how to replace the E53 Cooling/Aux fan?

I've heard of the complexities of the fan systems in our cars but this is the first time it's stared at me in the face...dang!

Thanks for posting all the details.

Unlike so many other posters that comes on this forum asking for help, but don't post the solution to their problem once it is solved, I believe that for the forum to be of any help to members solutions should be posted once the problem is solved.

Wow, that is one majorly fried fan. I'll be aware of looking out for the "genie" myself in the future thanks to this posting.

Ah yes, I do notice the cliffhanger posts with no resolution, and I appreciate those that do post up their solutions, thanks again.

Which reminds me, I need to go look the questions I've posted and see if I posted the solutions to the ones I've stumbled on the answers to. :D