I need to replace this actuator (motorcraft YH486);
I need more information on the "plastic knuckle" that the actuator lever attaches to as this is broken as well; Is it an assembly? Can I get away with replacing just the "knuckle" end?; I can't seem to find any part number info on it. Also, I need to replace the thin white vacuum tube that runs from the actuator into a wiring harness; can anyone tell me if I HAVE to remove it from the taped wiring harness that I assume runs through the fire wall; or if there is a replacement harness that makes the task easier? Where does the vacuum line terminate anyway?

Problem: Truck is getting hot, heat doesn't work, one hose hot; the other cold; I do have some air in the system (to be corrected same time as the actuator fix new thermostat installed and is working. As far as I know I don't have any head gasket leaks or heater core issues, as in the past the heater would just about roast me out of the cab! I appreciate any thoughts or advise offered

Thanks!
-Dan

 

On hose hot, one hose cold is a classic symptom of either air trapped in the system, or a plugged heater core.

 

Thank You Lead Head, can you offer any guidance on this question:

I need to replace the thin white vacuum tube that runs from the actuator into a ; can anyone tell me if I HAVE to remove it from the taped that I assume runs through the fire wall; or is there a that makes the task easier? Where does the https://www.ford-trucks.com/forums/1420899-1991-f150-hvac-recirculation-door-actuator.html# terminate?

 

You can visit any junkyard for the plastic knuckle piece, or fabricate any number of materials to make it work.

There isnt a replacement harness, and I wouldnt want to do that either.

Where is the white line broken? If it's broken in the engine compartment, just replace it from where it is taped up with the other vacuum lines with rubber/silicone vacuum line to the actuator line itself. Actually ALL the plastic vacuum lines should be replaced with rubber/silicone as they are getting brittle with age by now and barely moving them typically causes breakage. None of mine have broken behind the dash, theyve stayed fairly pliable out of the elements and away from the heat. Most of the problems originate right around where it is taped on the outside of the firewall, so start there.

That white vacuum line runs behind the dash along with all the others in a harness to the a/c control panel just above the radio - theres a small subharness that runs from the panel to the main harness for ease or working on it.