I have a 06 5.4xlt, First time it happened was July 4th, all of a sudden my a/c started blowing hot air. Even after turning it off for 15-20 minutes it would still blow hot air. Then last night it did the same thing... Plus I don't have the luxury of rolling my windows down and letting the air come in because I live in AZ so it's super hot any ideas what this could be?

 

if it was all of a sudden it could be a blown fuse or a bad pressure switch

 

Thanks, and Yeah, It happened twice within the 8 days. I'll be driving and all of a sudden it turns to hot air. Even if it's on full blast max a/c.

 

When it starts blowing hot, check to see if the compressor is working. If not, trouble shoot that. It could be electrical (fuse, relay, wiring by the exhaust manifold or elsewhere). It could be the ac clutch. If the electrical checks out, you could be low on refrigerant and the compressor is shutting itself off.
You could also have a faulty blend door motor.

 

Do weird noises come from behind your dash when the the fans are turning on to blow air? If yes, then its the blend door actuator motor. $50 part from the dealership. I just did mine. Took about an hour.

 

My A/C has been acting weird also but only when stopped in traffic or when I leave the truck running (with family inside) and run into the store it will start blowing warm-hot but as soon as we get moving cools right down

 

After 300,000 miles this is what I have learned. Mine was never really that good at cooling and over the years with charging and replacing every single part and still end up with crappy air it is finally fixed. I bought a 2015 and kept my 2006. Now I had time to just leave it at Ford with instructions that I don't care how much it costs or how long it takes, get it right. Evaporator pulled out while doing heater core (original). They had to do it twice since by looking at the side they could see, it looked fine and no dye detected. But when it still would not hold a good vacuum, they finally figured out to go all in and open up everything the other side was leaking, cruddy, and dyed, the side you could not see. Two years ago I replaced every part but the evaporator on the engine side of the firewall. Now found receiver dryer had a small seam leak. Replaced that. Radiator is clean, condenser is clean, hoses good. Fan clutch? Pressure would spike after start up and the fan would not pull enough air when cold to draw any heat through the radiator to engage the fan. Catch-22. Radiator hot, fan clutch has no way to take heat to engage. After 4 Ford fan clutches and sealing the gap all around the condensor with rubber to force the fan to draw all air through the condenser that it could, finally put in a heavy duty after market fan clutch. Now always pulls something through the radiator, even when cold but not so much to drag the engine. Condenser now has airflow all the time. I was about to put in an electric pusher fan, but all good now. 9 years later I am good. My best guess is that I had a high pressure leak in the evaporator from the beginning that would let out some freon down to a point but not all of it. It would never get below 1/2 charge but would never keep a full charge either. I just never had the guts to yank the dash out, worried that it would never be the same, worried that they would all be taken apart and then find the evaporator to be just fine. I have spent more that most people ever would on my old truck. Others would have given up and sold or traded by now. I have taken extremely good care of this truck even if I do plow snow with it. My goal was always 500,000 miles. As long as parts don't become obsolete, I will make it. By the way the 2015 has excellent air.

 

I don't have any helpful tips as there can be many parts in the a/c system that can fail and cause this but I feel your pain because I also live in AZ, Phoenix to be exact and this summer has been gnarly.

 

That's because Ford switched over to electric fans in the newer models.


My 2005 was converted (by me) to an electric fan; my current 2007 has been converted to an electric fan (same one that was in the 2005). At idle, my A/C blows cold.
As you have stated, the clutch style fans have a very tough time drawing in enough air flow to allow the A/C condenser to be efficient.
The air flow at idle is always going to be poor with the stock clutch type fan, and the A/C will appear not as cold.

 

My best guess is that a crappy fan clutch leads to poor condenser airflow. Poor condenser airflow leads to super high pressure in the system. High system pressure stresses every part in the loop. A leak in the system may only leak at super high pressure leading to erratic freon disappearances that are hard to find and correct. I was reluctant to get into the evaporator by pulling the dash but in the end that was probably what was wrong since the very beginning. I kept checking the drain water for dye and never found any. I just did not want to believe it was the evaporator since it sucked to replace and I could not find any signs that it was bad. I just assumed all of this generation had crappy a/c. I just can't imagine that Ford engineers when testing these trucks in Arizona for hot weather back in the design testing phase would have put up with bad a/c in the desert. I can't see them saying "gee, this a/c won't cool, lets just build them anyway screw it." Something in the original design had to have been compromised. Either materials or assembly was not right. Mine works excellent now, it just took 9 years and 300,000 miles to figure it all out.