Wifi no hardware installed but bluetooth and camera both work

Hello,

I've literally scoured the internet for solutions to this issue and have tried them all fruitlessly. Here's to hoping someone here has a better idea as to what's going on with my MBP.

Essentially, I have a grey icon with an X over it where the wi-fi icon should be, which when clicked, reads "wifi: no hardware installed." The other functions of the card and cable, bluetooth and the camera, perform correctly.

I have tried 3 different screen assemblies with the same effect. The logic board was recently replaced by Apple and is brand new. The issue persisted before and after the logic board replacement.

So, why would this be happening? Is it software related? You would think that with all the different hardware and the issue still persisting that it couldn't be the hardware.

I have tried several reinstalls of os x including 10.8, 10.9, and 10.10; the issue persists. I have tried accessing wifi from usb install drives and the recovery partition. I have tried all of the usual pram, smc resets, deleted plist files, held the power button down for elongated times during startup, etc.

I cannot access the apple hardware test (AHT) for whatever reason. I have taken it into the Apple Store and they have run the AHT and it has shown that the wifi is not working properly.

I'm convinced it's nothing in the screen assembly. Any help would be fantastic and greatly appreciated.

Thanks!