Hey all -

Seems like AC issues are commonplace on these vehicles but I am at a loss for figuring out whats going on with my truck.

I have 2005 F-150 Lariat Super Cab with Automatic Climate control. I got the truck recently and the A/C was not working consistently.

The previous owner had about $500 worth of service performed on the AC including a full leak test, evacuation and recharge. All of the solenoids seem fine, the charge is solid, and when it works right the air blows cold.

The first thing I did was replace the blend door actuator with a dorman part, that seemed to fix it for a day or two and then I started to have issues again. Then I replaced the actuator again with the Motorcraft Part AND replaced the blend door with the "heater treater" blend door.

I can verify blend door movement as right now I have the air box hole that I cut to install the heater treater wide open for testing.

Right now my issue is that the AC does not blow cold when the weather is somewhat mild. If it is 95 degrees out, the AC works fine - if it is only 70 degrees out, the AC will not blow cold, even if the cabin is quite warm - although without being 100% I would say the air coming out of the vents is slightly cooler than the ambient air.

I have tried putting the EATC down to 60 degrees, manually set it to max fan, and recirc and it still doesnt blow cold - this leads me to believe that it is not the cabin temperature sensor - as I imagine taking the EATC out of automatic mode would ignore any ambient temperature sensors, correct?

One other observation is that when the EATC is in auto mode, changing the temperature does affect the fan speed, for example if I turn the temperature down the fans blow harder as if to try to cool the cabin down more, if I turn it to max heat - hot air does come out - although I am not sure it is as hot as it should/could be.

I also performed the EATC self-test and I get no codes.

At this point I am at a loss. The only thing I am wondering about is - despite the blend door moving the actuator appearing to function, how can I verify it is actually working properly? Does it have a normal behavior I can observe to validate it is working right, or is the only way to pull the actuator again and test it with a multimeter?

One other thing is that the air mode door/actuator is very loud, almost grinding. However, the vents change between floor and defrost completely as expected so I am not sure that noise represents any sort of actual issue and I am fairly certain it has nothing to do with my temperature issues.

The most frustrating thing about the issue is that it is relatively difficult to reproduce, it would be very difficult for me to check for proper compressor operation as the issue seems to be completely weather dependent and it only seems to happen when I am driving - unless its just a coincidence that some other problem has occurred in line with the weather cooling down around here. I might be crazy but the AC seems to work most of the time when I am parked somewhere, as opposed to driving around - although this is not the case when I am simply at a red-light...

Looking for some help because I am really tired of grasping at straws and I feel like this issue is one of those problems that the average mechanic or dealership wouldn't be able to fix properly - especially given that various things have appeared to fix the issue only to have it come back some hours or days later.

Starting to think I might just be really unlucky and gotten a faulty blend door actuator.

 

Crawl under the truck with your feeler gauges and measure the compressor clutch gap for excessive wear.

 

What is your ambient temperature reading on your gauge? You could have a faulty ambient temp sensor. I would replace the sensor if it is off by more 20F.