Stick your head under there with a good light and make sure the pins that are present (not all are populated) are straight and clean.

If they are, then use a multimeter to check for voltage with the key in the #2 position based upon this pinout: On-board diagnostics - Wikipedia, the free encyclopedia

If you don't have power, you know the problem. Look first to fuses, I'd inspect and test them all unless you can find a wiring diagram that tells you which is for the OBD-II port.

Good luck.