No it doesn't actually matter which hose is connected to which port. The design of the Bronco heating system is for water to flow thru the core at all times. The flow is from the connection on the intake manafold behind the water neck to the core and back to the water pump.
Heat control is by a flapper door that controlls the mix of heated and cold air. The door is controlled mechanically by a cable. Make sure that cable moves the flapper. In a non A/C vehicle it is the cable that you can see by the fire wall on the right side of the truck. On a A/C vehicle, it is under the dash and can be seen by removing the glove compartment. If it moves freely back and forth when you move the control, then you may have some crap clogging the core or the air path.
A possibility is that your system is clogged with leaves. I had very poor air flow in mine due to the crappy design of the intake that allows leaves to easily get into the system. I had to take the dash cap off and remove sections of the duct work to clear all the crap out. Also check the fan control resistor area and the heater core fresh air side. I read of a guy that almost had a fire because of leaves around the resistor. To get at that area, remove the fan and use a shop vac to **** the junk out of that portion of the duct. I also removed the intake shroud behind the hood, the part with slots in it (requires removing the wiper blade arms), to clean out all the crap that had collected in there. I don't understand why Ford did this, but they have a rubber bladder at the bottom of the intake. Rather than keeping crap out while letting water out, it does just the opposite, it keeps leaves and crap from clearing out. You can't actually see this thing unless you remove the fender. I used a metal rod to loosen the crap and sucked it up with my shop vac. Ford addressed the leaf problem in the late 80's by making the grid work in the shroud with small holes rather than slots.
Another check is to feel the hoses to see if one is hot while the other is cool as the engine heats up. They should have just about the same temperature. If the return hose is cooler than the supply hose that indicates a restriction in the system. One thing you can do is remove the hoses and try to blast it out with a water or air hose. If it is not completely clogged a trick is to reverse the hoses which sometimes clears the junk out. You might want to consider getting a flush kit and flushing the entire system, which will help to make the engine cooling system more efficient by cleaning out a lot of old crap that collects on the inside of the water channels.
If all else fails, then you most likely will have to replace the core.
Hope that helps
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Good luck,
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