Toner

Having issues with the brake light switch on my 11 MKX. Original has a sticking plunger, but otherwise works. Plugged in and hanging, brake lights come on. Depress plunger and they go out. Picked up a replacement from Napa and it looks identical, but plug it in and get nothing, no lights. Returned it and grabbed one from Autozone, but same problem. Got a third one from a dealership (SW7810), same thing. The odd's of getting three bad one's has to be near zero, but since the original still works I don't suspect wiring. Stamp on original has a number 8t4t-96854-aa. Any help is much appreciated.