I have only seen cases where the DME had corrosion from coolant leaking down the wiring from the tstat connector making it's way to the DME and causing a fan activation issue. I have also seen on a higher mileage e39 540i the vanos solenoid allowing oil to leak through them, down the wiring into the DME connections as well. There would be obvious signs of an issue when physically checking the DME connectors...

No signs of any issues at the DME. Corrosion free. Its important to remember where I live though. Like EODguy I'm in the desert and our temps here along with the low humidity can cause electronics to fail.

The wire is good between the DME and the fan as it gets variable voltage and a signal. The signal is supposed to be a square wave but a scope shows that is not the case with this DME. The DME also is unable to see the fan acknowledgement at startup (as the fan doesn't get a correct signal...it doesn't turn on...and so the voltage generation is not seen by the DME) and sets a code for Fan Activation error.

I've grown accustomed to electronics failure in vehicles. If you recall, I had an ABS unit fail that actually caused my car to go into Trans Failsafe with a code for a bad transmission speed sensor. Turns out the ABS unit and the Trans Control Unit had a disagreement on the speed of the vehicle and the E53 assumed it was a trans issue and not ABS. Sent out the ABS for a rebuild and all the gremlins were gone again. I'm going to hazard a guess that once I have this DME rebuilt that the brand new fan will indeed work. If not, then I'm at a loss and will look at it again. :)

You are probably correct but It might be worth trying to get a spare DME, EWS and key just to see if the spare DME will activate the fan. You may be able to just plug in the spare used DME and see if it will activate the aux fan. The full pkg is really only required if you plan to start the vehicle. I have a few spare 4.4 mE7.2 DMEs which should be sufficient to use as a test...

Let me make sure I have this idea right...get another DME/EWS pairing and a key that's stored in the EWS. Install the DME and EWS...and then also change the lock cylinder so the key turns....and then check the fan activation?

Couldn't I just code another DME to my VIN and synch it to my existing EWS using my Foxwell and get the same result or am I missing something?

DMEs are a 1 time write so that can't be done without specialized tools and alot of me7.2 knowledge to erase the ISN so you cant pair a used one as the EWS will never accept it due to the mismatching ISN. However, for testing purposes I think you can just plug in the used DME turn the ingition on (DO NOT attempt to crank it which may unpair the original EWS and original DME which can be repaired easily since it has your original matching ISN as long as you have some kind of software that can pair them back up) and see if the foxwell will activate the aux fan.

Here is a good example on e38 bimmerforums: see post #36
I think he is also in Florida

https://www.bimmerforums.com/forum/s...-on&styleid=50

For fan activation purposes any same type DME will do the job.

A used DME can be cloned for your VIN and EWS info. Some modules like diesel DDE4 there is only one 8 leg chip (ST Microelectronics) (same type as on instrument cluster) which contains this data and can be swapped from original ECU.

I've got the DME and EWS packaged up. I also purchased a used and matching DME so they can clone it for me as well (and I can put it on a shelf).

I've never found a way in Foxwell to activate the fan ...but I do have INPA so I can get around it.

There are a few ways that *should* activate the fan. I looked into that when confirming my fan was dead. The following thread has a bunch of off topic stuff, but if you can sort through that, there is good info in there:

https://xoutpost.com/bmw-sav-forums/...-fan-woes.html

I know it is often a treasure hunt to find the Foxwell features you know should exist. Here is the sequence that runs the fan active test on my 2001 3.0i using my Foxwell NT520 Pro:

You start by going into the BMW diagnostics and do the automatic VIN ID (that no longer works on my car) or manually tell it what model you have.

When you run the actual test by hitting the F3 button to "activate" it will do nothing for a second or two, then gradually ramp up the speed over about 10 seconds, holding it there for a few seconds before spinning it down. Very impressive I have to say.

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EDIT - also, I never ever got any codes related to the dead fan. BTW, finally and completely confirmed dead when the replacement fan worked perfectly. As far as I can tell, that Foxwell test sends commands through the ECU to the fan, and you are supposed to watch to see what happens. There is no success or failure signal that comes back.

Cool! I was looking for fan activation on my NT520 Pro. My fan works. I installed an aftermarket brushless fan. I'm still looking into why it does not start up at A/C demand. Once the engine is warm, the fan kicks on. It ramps up on heat demand.

ok...so, I just got another Foxwell scanner (530)...and I'm hunting for this exact menu. Can you give me the tree? I've gone into Diagnosis, DME...but no active test menu. It gives me ECU info, Read Codes, and Clear Codes ...