I I am SO tired of everything needing to be controlled by the computer on modern cars! Even things like turning the KEY to start the engine don't just close a relay anymore... No, that key signal ONLY goes to the computer, which then decides whether to allow the engine to crank or not. If your airbags deploy (or you buy a boneyard ECM from one that did) you can't even check the computer by starting the engine - The computer won't allow the starter to even CRANK if it thinks the airbags went off! I guess this is a "safety" design, to force you to tow it to a dealership who can reset your wallet.

That is totally false,the PCM has nothing to do with the airbag system besides suppling some info for the SRS module like speed,brake applied,and other info.Will not cause a vehicle from starting if the airbags deployed.I worked in a bodyshop and can varify I have never had a vehicle not start if the airbags deployed,of course if the engine compartment was not damaged enough to hinder proper operation like the radiator pushed into the fan.

No resetting ever done,can not be done either.

You may have spent time huffing paint in a body shop, but that doesn't give you experience that trumps a real-world situation.

I purchased a boneyard ECM from a CRD that had blown airbags. I have no clue about the rest of the status of the engine / vehicle, as the engine was not present in the shell that the yard had.

HOWEVER - I do know what the CRD will do when the SKREEM module and the ECM don't agree about what the keycode is: The engine will crank and start as normal, but will be shut off within 2 seconds. This boneyard ECM would only allow a 1/2 revolution of the engine from the starter, then the starter would not engage again. Cleared the codes from that ECM, same result. The codes were just the usual "MAP / MAF problems, EGR failure" from a high mileage fully-stock CRD. The test bed was in MY WORKING CRD, which I had driven to the boneyard to purchase this boneyard ECM. Once I put my own ECM back in, the engine started instantly.

There were no other codes in any other system when the boneyard ECM was plugged in - ABS / airbags / BCM etc were all clear. Yet the boneyard ECM would not allow the engine to crank.

The ECM was subsequently sent to GDE, who was able to re-stock the program, and sent to Sebastian in Argentina who is now driving around on it.
THE COMPUTER WAS NOT ALLOWING THE ENGINE TO CRANK because the airbags had been deployed.

The electric fan has several inputs for the relay control including vehicle speed, ambient air temp, AC head pressure, transmission fluid temp, fuel temp and coolant temp. Usually with the AC on max fresh air the head pressure will cause at least the low speed fan to turn on.