On an older Ford i was told never to use MAX AC on anything other than blower 4, as it might damage the AC in some way. If i wanted a different fan speed then i need to switch to the head or feet button. Is the true, or can i set the MAX AC on various fan speeds?

 

While I've never actually heard this "rumor" I do some what practice it. I usually try to run my blower on 3 or 4 if in the max AC mode. Reason being, I've been on long road trips with friends that would use max AC and run the blower or 1 or 2 and the AC would freeze up. This ,however, was a few years back (~95 model vehicles) which probably had R12 freon, but its something I've alway remembered and thats the reason I run on 3 or 4 and I've never had a problem in any of my vehicles using max this way.

 

You can use whatever speed you want.If the system starts to freeze the computer will just turn the compressor off for a few seconds. That is why they call it a cycling system.

Mike

 

That and it doesn't blow cold enough to freeze anything.

 

I started liking the Max AC position when I bought my 94 F150 and read in the owners manual that Max AC improved gas mileage. The book for my 01 Ranger 150 hp 6 cyl. said the same thing.

I did not find the same statement in my 04 book-hope that I just missed it. At 14.x mpg in my normal around-town driving and $1.77/gal. today, I can use any help that I can get! I'm afraid that the AC switch can't give me the help that I'd like to have. Also, I enjoy driving the truck so much that I can't complain about a thing. The 04 5.4L actually gets slightly better mileage than the 94 which had the 5.0L

Anyway, back to the point, I have used all the fan speeds and always go to 1 or 2 on the highway. Never had a freeze-up or any AC problem. I've been using Max AC for 8 years in the three trucks. In Texas, Max is our best friend for what seems like 9 or 10 months out of the year.

jimmyj
04 F150 SCab XLT 5.4L in Dark Shadow Gray
P.S. Texas has 4 seasons, you know, Almost Summer, Summer, Still Summer and Christmas!

 

I've always used max (don't have a choice in Tucson) and never have had it freeze up on me in any vehicle I've owned.

 

I agree that this new A/C system in the F150 isn't going to freeze anything. For those of you that have one of the FEW 2004 F150's with such GREAT A/C consider yourself lucky. While mine does a fair job, that's all it does. I work daily in a 48 degree or below environment so I know what cool feels like. I come out in the 90 degree heat and 80% humid air of Georgia and its like I hit a brick wall. Why is it that my 97 F150 will cool down to the point I have to turn the blower down or direct the vents away from me, yet my 2004 F150 does good to keep me slightly comfortable? Forget sitting still with the A/C running because it converts over to nothing more than a fan that blows maybe 55 degree air but nothing colder. I call my service advisor and he tells me that he hasn't heard anything about the A/C not cooling at idle sitting still.

 

i only use max ac to cool the cab initially, then switch it to reg ac from then on. with the black interier that i have, the max ac cools the interier quicker and then the reg ac keeps up just fine. have always been told to run the ac that way but never been told that you have to run a certain fan speed in a certain setting. never have had an ac system freeze up even on the lower fan speeds, but each is to their own.

 

The difference between Max A/C and A/C is that Max is recirculated air, and regular A/C is fresh outside air. I believe that you are better off running Max most of the time because your A/C is having to cool air that is considerably cooler than the outside air, thus it has to work less and is more effecient. You may want fresh air in the cab sometimes, especially after eating Mexican food, but for effeciency run your A/C on Max. As an additional note, I got a letter from Ford when I bought my '01 that said not to park the truck with the A/C in the Max position, or the Off position. The reason being that those 2 positions seal off the outside air from the evaporator which could cause mold and mildew to form. This could lead to a "bad smell" when starting the vehicle and turning on the A/C.

 

Thanks guys for the inputs, been using MAX all the time now, with it being 94 with about 80% humidity here in Louisiana it has been nice.

 

Austin,
I always have always been told to turn of the AC so that it will not turn on the truck when you start it up. If what you say is true then that is why I now have a smelly AC. I just have been told that if you have the AC on when you start up it strains the truck some how. What setting do you have it one when you shut down?

 

But isn't the air-conditioner clutch automatically disabled during engine start and hard acceleration?

 

The system kills the AC and other accesories when you turn the key to ignition (start) position. LSU, if you have a smelly AC you probably have a mold inside your AC ducts and if so you will need a commercial grade disinfectant to kill it. Lysol and other stuff from walmart usually wont kill the smell. There are "how to" posts on this site.

I agree with the earlier posts. The AC system on my 97 F150 has never been opened or repaired. Today it still works way way better than the AC on my son's brand new 2004 regular cab. His 04 AC is not terrible, but it barely gets the job done in Houston. My guess is Ford saved a little money and reduced truck weight by downsizing the AC capacity. If the AC in my son's regular cab was installed in a screw cab or supercab, I would not buy either truck as there is no way the AC could cool the back seat area. Ford needs to think hard about improving the AC system. I will replace my 1997 soon but i am not buying a truck of any make that cant cope with south texas weather. I test drove a Titan screw cab last week and the AC in that truck was great.

 

if i want to use the disinfectant how do i get it in the system?

 

Maybe we should do a poll. You say that the minority are those that have the cold AC, how do you know that? It's the same with all the other issues with the truck here. My bet is the majority of the trucks are fine and the "issues" are in the minority. We all want everyone to get the best of their trucks. I still can't understand why your AC is not cooling if it is blowing out 55* air. Why does that not cool down your truck? Why would you need it cooler than 55* to bring down the heat? This is ignorance on my part. Maybe I don't understand how the AC works.