Can't unplug wire harness... HELP!

Does anyone out there know why the smaller wire harnesses on my AC/Heater fan assembly won't come unplugged? My fan chirps like crazy and I want to try lubricating the bearings. I removed the fan assembly from underneath the glove box, and unplugged the larger wire harness located under the dash, but I can't get the smaller one unplugged from the fan assembly. It seems to be completely locked in.

It's rare that I run into a DIY project on my truck that I can't tackle, but I'm about to give up on this one. I'm worried I might damage the harness if I keep messing with it. Any advise or tips would be greatly appreciated.

 

Mine was a bitch. I couldn't press the clip down far enough on the wiring harness to disengage it with just my fingers. I took a small flat head screw driver and pushed it between the clip of the wiring harness and the fan assembly. Press the clip down with the screw driver and and pull on the wiring harness. It should come loose.