My 1996 is blowing very hot air out of the floor vents even with the ventilation turned off and the temperature set to cold, the hot air blows harder and hotter the faster I drive and stops blowing when the vehicle comes to a stop, it gets so hot sometimes that it nearly burns my feet, im not sure if it's a contributing factor but my A/C also isn't working but that might be a separate issue, any ideas what might be going on? Thank you.

 

Welcome to the forum

You have at least 3 separate issues maybe 4
AC is a separate issue

COLD and HOT **** controls an electric Blend Door, it moves to send air from the fan either thru the heater core(HOT), or around the heater core(COLD)

The Vents, defrost, panel, floor, are Vacuum controlled, not electric, but..........Defrost is the Default Vent, i.e. no vacuum = Defrost, not floor

Fan speed, this is electric, and you say the fan speed/air speed changes with RPMs, or is it just vehicle speed?


There is one common part for all, the Climate Control Panel, the 3 *****, but ALL 3 are separate systems, so to have all 3 break at the same time would be very very......very long odds
Unless there has been some work done under/behind the dash, like new radio or ???


Google: Ford Ranger blend door

So you know where it is
Key on engine OFF
Move the Temp **** to cold and hot and listen for the door to move, its not that quiet
If no noise check Fuse 10 in CAB fuse box, 7.5amp

Also test Fan speeds at this time, the Vent **** needs to be moved to any position EXCEPT OFF to test fan speeds
Fan uses a Blower Motor Resistor block in engine bay for all speeds except HIGH, so if only High works then the resistor block needs to be changed

Now the VENTS, look here: https://www.ford-trucks.com/forums/a...ntid=517&stc=1

It looks more complicated than it is, lol
The air flow comes from the right
The Blend Door just controls TEMP it can't block air flow, it just routes the air thru heater core or around it
At the Lower left, are the 2 main vent doors
Panel/Defrost
Floor/Panel
Each has a V for vacuum, or NV for no vacuum, PV is partial vacuum position

If the floor/panel door is broken then it may be stuck "down" so all air goes to the floor vents, and since its the FIRST door the air flow gets to then none of the other Vent setting would work

The vacuum hoses that run to the "vacuum motors" look like wires, seen here: https://www.ford-trucks.com/forums/a...3&d=1501791993

You can look under the dash to see where each color goes to find the floor/panel door, the yellow and blue hoses

 

Thank you for the very informative response. First, Yes the previous owner did install a new radio. Second, selecting a setting on the vent **** will activate the fan but will not blow air out of the selected vent until the engine has been turned on, so it needs an active vaccume to make the adjustment, but if the truck is in motion, air will blow out the floor vents in addition to (and regardless of) whatever is selected, so I can still get panal and defrost ventilation, but im always getting floor ventilation no matter what. Third, the speed of the air coming out of the floor vents is directly regulated by the speed of the vehicle, not the RPMs, its as if something is allowing air from outside to freely pass through the harter core and enter the cab without any hindrance. Fourth, Im able to hear the blend door moving when I turn the temperature ****, but no matter what its set to it just blows hot air. And finally, I can confirm that all the fan speed settings are work appropriately.

 

The cab vent system vacuum comes from a vacuum reservoir located at the front passenger side of engine bay, down low, so Vents should have vacuum all the time, engine off or on
The Reservoir looks like a black plastic ball, well it IS a black plastic ball, lol
Its located down low at the front of engine bay, passenger side, this is a picture of its location with fender removed: https://www.explorerforum.com/forums...obe-jpg.39621/
Its the black ball, no, you don't have to remove the fender to get to it, pic is just so you know where to look for it from inside of engine bay

It will have 2 black hard plastic vacuum hoses attached, one goes to the engine's intake manifold, the vacuum source, check this hose
The other one runs to the firewall, this is the one that often has breaks or melted spots near exhaust pipes, follow it and check it for damage
It reads like either this hose is damaged OR the vacuum reservoir is cracked(leaking) so you only have vacuum with engine running and its only high vacuum at idle

These hoses can be patched and replace with regular vacuum hose, the hard plastic hose is just cheaper for Ford to use
There is also a Grey vacuum hose in engine bay hooked to Heater Hose By-Pass valve, you can follow it over to the firewall, the grey hose and black hose go thru firewall at the same hole
Inside the cab the two hoses look like this, red arrow: https://imgur.com/AHlTteI

Grey changes to white inside the cab, Black stays black


If the temp doesn't change when you rotate the Temp **** then Blend Door is not actually moving even though you hear the motor moving, which is not a good sign, it means door could be broken
You can cut a hole in the air box behind glove box, there is a video for that, big enough hole so you can reach inside and see if you can move the Blend Door manually, if you can then its broken, or the electric motors shaft is broken
The Blend Door system is simple, direct air thru the heater core or around it, so temp of air HAS TO CHANGE if its working(assumes heater is warmed up), so not a debatable diagnosis, the door works or it doesn't


The Fresh air opening for the fan is under the cowl in front of the windshield, so there is no way for vehicle speed to effect air flow thru the vents
So something has changed in that set up
Maybe the vacuum system is cause a shift in vent doors for better air flow as vacuum changes during acceleration(low vacuum) and cruising(higher vacuum)
So this part is a puzzler

Its possible, but not likely, that the electrical system powering the fan/blower is getting higher voltage from Alternator so blows more air, but you should notice that via any lights that are on at the time, they would get brighter and dimmer if this was an alternator issues
Alternators are setup so they produce no lower than 13.5volts and no higher than 14.9volts, unless they break, lol