The description says it all. I've read over many forums and I am still not sure of my problem. I have a 2002 f150 supercrew 5.4 liter. About mid winter my heat suddenly went from hot to lukewarm. A check of the fluids shows all is good. I use my truck solely for work so I didn't bother with it at the time. Summer is here and my AC blows kinda cold, at best. I can hear the blend door moving. The temp control does make a huge difference. It just doesn't get real cold or real hot. Not like it should. Please point me in the right direction. Thanks!

 

I'll bet the temp door broke. It's not uncommon. It will still move, but it won't seal in either direction.

I've fixed several of these. I used a kit from HeaterTreater. It is much stronger than stock and easier to install.

 

I would assume this is the blend door you are referring too?

 

Yes it is.

 

The door can clearly be heard moving. Which is why I am so unsure on this. I don't want to tear into it and that not be the issue.

 

Do you know the door goes all the way to both cold and hot positions? It can break and still move, but then you get a mixture of hot and cold all the time. You would have cool but not cold AC, and warm but not hot heat.

 

Is it possible that the heater core could be plugged and giving me this issue? I'm just trying to cover all my bases. Thanks again.

 

Yes, a plugged heater core will result in lukewarm heat. How will less heat make the AC blow warmer?

 

I agree it wouldn't make much sense. Just thought I'd ask in case I was over looking something. Should I go ahead and change the heater core while I'm in there? Can the heater core be changed while using the method the heater treater uses? Or would I have to remove the dash to do the core?

 

I wouldn't change the heater core unless it's leaking. The Heater Treater method doesn't get near the heater core.

 

Thanks for all the input. I watched the heater treater video for f150s but I have the super crew cab. So I have a vent that runs to the back seats. I will have to try to figure out how to get past this vent to access the actuator without cutting my carpet. Not fun at this point.

 

So I removed the blend door actuator and checked out the bottom of the blend door. It appears to be fully intact. I used a screw driver and manually turned the blend door. It turns freely. At this point I do not believe the blend door is the issue. Compressor is working and AC coolant is at proper levels. Any other thoughts on what it could be? I think I am going to do a full coolant system flush to see if that helps.many further input would be great. Thanks

 

the heater and air conditioner have very little to do with each other except for the blower motor and the temp blend door. If the R134 is up to 35 psi on the low side and about 200 on the high side, you should have cold air. Normally "proper level" can be visually checked by seeing if the compressor stays engaged most of the time. If it is off or constantly kicking out, it might be low on charge.

 

post #19 in the link below shows the vacuum doors and blend door functions. IN "max air" you shut off outside air and keep recycling the inside air so it gets colder and colder.


https://www.ford-trucks.com/forums/9...-please-2.html

 

I have 35 on the low side but I do not have the tools to measure the high side. The compressor runs nonstop that I have seen and it does not make any odd sounds. At this point I am pretty much confused as can be. Unless there is some way that the blend door is broken without me being able to see it? I have no idea what the problem is and I might have to take it to a mechanic.