First of all, hello! I am new to this forum but it seems like a great community! My username is based off my truck's name and my favorite number :) The truck was my grandpa's. He added a nice exhaust system, an oversized air intake and filter, and some nice steel wheels with oversized tires. I love Lucky and my grandpa a lot, and I really want to keep this truck in pristine condition.
I have a 2011 4.0 V6 Ranger XLT.
As the weather has gotten colder, my air system stopped blowing. You can hear it running and there is a very small amount of air coming out (like, put your hand on the vent and you can make out a bit of hotish air). THIS IS ONLY HAPPENING WHEN IT IS COLD OUTSIDE. Before today it was only happening in the morning, but today was our first small snowfall, and apparently that was cold enough to make the air system stop working again. The thing is, if I warm up my truck, or drive around for about 10 minutes, the air suddenly works fine, full blast, super strong and hot.
Suspicion lies on the blend doors at the moment, but I'm hoping its some kind of electrical hiccup. I saw another thread that kind of sounded like it that was about "Cabin HVAC Fan Relay Socket" from FiremanBob
I just cleaned my air filter out yesterday (its a performance, no oil required, reusable one) and I recently got the thermostat and thermostat housing replaced because of a coolant leak, so neither of those could be the issue.
If you need more information specific to something you think it might be, feel free to ask. I'm not well versed in the car-world even though I love cars, but I will do my best. Thank you for any and all help!

 

Welcome to the forum

The Blend door just controls TEMP, nothing to do with Fan and air Flow, its just points air thru the heater core(HOT) or around the heater core(COLD)

You should be able to HEAR the fan, turn down the radio, lol
If you are not hearing the fan then its a fan/blower issue

Air Direction is done using engine Vacuum, Defrost, Panel, Floor, directions are all vacuum controlled, Defrost is Default direction if there is no vacuum available
There is no position where these "doors" can block air flow, they direct air flow, so if air is not coming out Defrost vent then its coming out Panel or Floor vents, and visa versa

If you think its the fan, then pull it out, 3 screws, and check to see if the "squirrel cage" is tight on the shaft of the motor, they can loosen up so motor turns but fan blades don't
Also reach in the fan motors hole and to the right(drivers side) and feel the back side of the Evaporator fins, make sure there is no debris in there, as that WILL block air flow
Also up to make sure fresh air hole is clear

AC is used all the time, summer and winter, and in colder weather if AC is low on "freon" it can FREEZE in the Evaporator, blocking air flow
If you think that might be happening then UNPLUG the compressor's Clutch to keep AC off for now and see if problem goes away, long shot

 

Thank you! I've been telling the guys at local shops that I think it could be freezing and they wouldn't believe me! tried to get a ton of money out of me to just check the blend doors too. I guess they don't know much. I will be trying the things you said as soon as I can tomorrow.
I feel like it must be a freezing issue since it only doesn't work for a little while. Must mean it melts everything eventually. As for defroster, it also won't work just like every other setting. Does that change what the problem could be?

 

Defrost is a Vent(air direction) setting, nothing to do with the Fan's ability to push air out

Fan must be working FIRST, and that air flow can pass thru Evaporator and into the cab FIRST
So thats the place to start

 

Update:
I opened up the fan and looked at the motor and all other pieces. Everything looks clean and operable. I also checked the fuses for every aspect of the motor and ac in general. All of it looked fine. No moisture seen, so couldn't be a freezing issue. I talked to a guy at my local dealership and he had never heard of such a thing happening. Ugh, literally I am the only one to ever have this issue apparently. I guess if it comes to it I'll end up replacing basically the entire system.

Question:
Could the compressor be having issues? Since it is getting colder, is it having problems building pressure? I suppose I could go get my pressure tested. But that still wouldn't account for the defroster also not working.

New thought:
Could it be the battery? There is a small amount of corrosion on one of the ports and I also have an LED light system connected directly to the ports. I don't think they drain any power while off, though. Is the alternator charging the battery up enough after 15ish minutes to finally turn on the ac? I've never heard of such a thing.

 

Final Update:
Oh boy, I am dumb. I checked all the fuses before I began and thought they were all okay. Uh oh. Nope, the 10a fuse for PCM had blown. Replace that and we are golden. And just in time, too, because this is the first day over here in Spokane that we got snow on the ground. I guess if anyone ever has this problem, check, double check, triple check your fuses.

 

Good work

Thanks for the update and THE FIX, it WILL help someone else down the road

 

Welp... It stopped working again. All fuses are intact this time. I might try replacing the resistor or the blower motor itself.

 

Test connector at Blower motor see if it has Battery Voltage, when switch is at HIGH, then see what voltage is at Medium, should be lower but not 0volt

 

Yea, I did some snooping and that's seems like the next viable option. I'll buy a voltage tester soon. According to some people, if the blower is bad, you should get a new resistor as well. Totals around $100.