The first guys diagram is off a 1997 f150 so don't pay any attention to that. Now open your glove box and take out the 6 screws that go around the cover the are 8mm heads and it pulls away and there is the heater core. On the outside you will see the lines going into the heater core they are plastic connectors so don't break them. Push in the white plastic tabs and pull back if the whit plastic breaks it is good because you will need to replace them anyway. And then pull out the core.