Forward Cooling Fan Replacement

[Neil]

I've been having problems with the cooling fan on my 2014 Rex, apparently the fan has failed resulting in the CEL. I brought my car into the dealer to actually run the HV battery test as my 10 year battery warranty is up in a few months. They attempted to run the battery test but said it was being halted because of this dead fan. They wanted $1800 P&L to fix this which I thought was a bit high and that I'd have to think about it. More like try to do it myself first or find a shop. The new fans aren't cheap in any case but I'll try to find a used one. In any case, has anyone changed this fan before and can you offer any tips on the best way to get at it. I started taking apart the stuff in the way, but what might be the last thing in the way is the cross brace which I've gotten loose but it won't come out yet.

Here's a picture of the fan (not mine, a used one on ebay):

And here's a picture of the front compartment with the cross brace above the fan, with red circles around the trouble spots.


Has anyone done this before? Any advice on how you got this cross bar out?
TIA

 

[alohart]

I sent you a private message (they seem to be called "Conversations" in this new forum software).

 

[Neil]

Quick update- I found a used fan from a 2017 i3 and through much effort and improvisation, managed to change it. I was able to see it run before installing but having it plugged in and also after fully installing it. I thought it was fixed but a short time after replacement and seeing the CEL off, it came back on with the exact same fault scan items that were present with the original fan which are the following:

Does anyone have any suggestions of what else could be causing these faults?

 

[mojo]

Just a generic observation - not specifically about i3's: Modern cars typically have a PWM controller which allows the engine management system to control the speed of the fan. It may be that this has failed?

Is it fair to assume that you have a good chassis ground at the connector?

 

[Neil]

I was trying to and may still try to put a PWM signal into the control line of the original fan, although I'm speculating that it might be a single wire communication bus. There is no ground connection that I know of near the fan connector, but I was able to trace the cable back to a connector on a module nearby, removed that connector, inspected, cleaned and replaced. No change. Maybe the issue is in that module. BMW originally told me that they couldn't activate the fan with their software, so the fan must be bad and would replace it for $1800 and could therefore not run the battery test. I did find a used fan, 3 years newer, and like I said, experienced the same problem after I saw it run, and BMW was able to get that fan to run while doing the battery capacity test which they were not able to do with the original fan. It seems to indicate the root cause is not the fan.