I have a 1999 f150 4.6 liter heater core was changed and temperature selectors were changed but don't have any heat why would that be ??????

 

That would be (most likely) because you haven't found and corrected the actual problem.

 

Low coolant, bad heater control valve (I can't even remember if we have one), blend door stuck, who knows.

Need more info. Do the heater hoses to the core get hot? Does it blow at all? Does it blow out the proper vents?

 

My heat stopped working in my 98 a few months back. Ended up being the blend door.

 

I have put it on defrost and it blows out the windsheild. Vent and all the other vents gets up to temp but blows cold and is full on fluids and the hoses do get hot that happened in my wife's sport trac and it was one of the sensors on the water outlet

 

Yes yes and yes

 

I would say that if both the heater hoses get hot, then coolant is flowing through the core, so it must be a blend door, but I'm not really familiar with the layout of the doors.