My 99 Ford Ranger only blows air though the dash defrost. It doesn't matter if I have vent or any other selection. And it only works WIDE OPEN. I also am having a problem figuring out where a plug goes. It comes from the same wiring set that plugs into all the heater core wires come from. Also have something (don't know how to describe it) but it comes from under neath the radiator coolant, its a black small tube with a white plastic tip on the end?
PLEASE HELP ME?!?!

 

the blower resistor needs to be replaced (fan stuck on high). it's located on the heater box right behind the passenger tire.

then you have a vacuum leak. that's why it's stuck on defrost. likely on the passenger inner fender. the "plug" may be the vacuum line that's off. it may go to the heater core bypass valve.

 

Ok my blower resistor needs to be replaced. And I found there was a mis-connection which caused the vacuum line that some how became unplugged. But What I need help with now is my heat doesn't blow hot. Not even warm. Thermostat or Temperature Value?

 

Search the site for blend door actuator. That has been the most common problem in the past.

 

My connector came off on the control box, easy to find once you have the face plate is off and radio out. Flashlight, and look down to the left. The lines look like large wires, and are colored(red and white on my 2003), but you can tell there different. The control valve in the engine bay, plastic on new. Don't know type on older. go out regularly, Located behind the A/C system, kind of floating in the air, some might have 4 coolant lines, some only two, check it and vacuum line that goes to it. If the valve is no good, it will not allow hot coolant to go into the heater core. Good system, if heater core goes out. unplug vacuum line, and not hot coolant in floorboard.