Even if there wasn't a code for a bad aux fan, they could have used BMW diagnostic software to command the fan to turn on and off without having to remove the bumper.

Considering an OEM Aux fan is between 500 - 600 bucks and it's a 4 hours job to replace the fan, 1200 is probably a so so price from the dealer to perform this work.

I get it. I was sure there was a procedure for testing the fan, but wasn’t privy to what it was. Eventually I talked to the shop foreman, and he said they had a procedure to test the fan input using an oscilloscope, since it was a PWM signal. I was concerned because somewhere along the line the service advisor said the fan was working ‘intermittently’ and I wanted to make sure it was not some controller issue (like the AUC sensor or other). They may not have had to remove the bumper to do this, but I suspect they may have already, figuring I was just going to okay them changing the fan, but when I didn’t, they threw it back together, poorly at best..

Point is, they didn’t test the fan when asked (repeatedly). Told me instead the fan was fine. Jerked me around for two weeks, performed unnecessary services to the car, even after I indicated (again repeatedly) that I did not believe that to be the issue, and did not agree with the symptoms they were telling me they were seeing (warm middle vents, cool outer).

It seems to me the techs either have NO ABILITY to troubleshoot an issue, or are too damn lazy to try. They simply follow some generic procedure for A/C not cold. Don’t even bother to listen to the details that it is cold underway, warm at a stop (dead giveaway, especially give how common this issue seems to be).

As for the price, maybe, but it took me about 4 hours to replace the fan, if it takes a BMW tech that long to do it, that doesn’t seem like a very experienced tech to me. I’m sure there is plenty of mark-up in the part as well. AND NOTHING, I REPEAT NOTHING WARRANTS DAMAGING A CUSTOMER’S CAR INTENTIONALLY BECAUSE YOU DIDN’T GET THE WORK.

No, I can’t prove it, or I would be making them pay for the repair, but I can assure you I will NEVER take my vehicle back there, between the total incompetence of the diagnosis process, and now this..

Rant Off..

The PWM signal is sent by the DME to the control circuit in the fan. Although an oscilloscope such as a Picoscope can be used used to verify that the DME is providing this signal the oscilloscope can only tell if the fan is bad if the signal is present, but he fan doesn't turn on.

Here's a thread that I started when I encounter a bad aux fan on my X.

http://www.xoutpost.com/bmw-sav-foru...fan-fault.html

Just because he's a tech doesn't mean he work any faster than you. It will take the tech the same amount of time to replace a tire as the average guy. He may be able to shave some time off, but the dealership will still charge you the book time allocated for the job.