On my 95 Mark 8 I do not have the self test plug just the 6 pin connector. So I bought a test reader and when I hooked it up the fan came on but no numbers on the led screen. Is there another way I can retrieve the codes?
It's doubtful it fell off as you'd have wires dangling there (Unless someone taped them up or something.)
It sounds like your using the right connector. Did you hook the single wire with the connector to the tester as well (it should be with the test connector, see attachment)?
I just noticed in your original post that you said "I do not have the self test plug just the 6 pin connector." Maybe I misunderstood what you meant, but the self test plug and the 6 pin connector are the same thing.
To pull the codes your using the right connector though from the sounds of it.
Also look over the manual again for your code tester and see if you missed something in the setup or operation of it...