Hot here in North Carolina as in lots of places, my PSD F250 175k miles has a problem with the max a/c. When the setting is on max the cool air is diverted to the defroster vents, the air is cool and at a very high velosity, just wanna devert it to the dash vents. Any ideas it all seems to be vacumm hoses and no mechanical levers.
tks for looking at my problem
Hot in NC

 

Check the hose that goes to the recirculating air gate. On my '99 it's under the glovebox inside the truck. On my '95 it was under the hood next to the right side hinge. You're losing vacuum somewhere. All vacuum controlled climate control systems are designed to fail to defrost so you can at least clear you window if need be.

 

I had the same problem it turned outto be a vacum swith in the dash. Is it only on the max A/C or does it do it on other setting.

 

Once again you have saved me a lot of money. I'm pretty embarrassed about this,,,, but if I can save someone else the headache that I've had the past two months, I guess it would be worth it. I bought a 99 F-350 back on June 17th. I live in South Texas (San Antonio) and it gets pretty hot down here in June, July, and August. I've had a simular issue with my A/C. It would blow real hard on Normal A/C, but when I'd turn it to MAX A/C, the flow of air decreased about 75%. It would never get real cold either. I went on a trip about a month ago and never turned down the fan from high the entire trip(about 550 round trip). I put a temp guage on one of the vents, and if I was running down the road it would get to about 50 degrees. After the trip added some freon, still no help. So, I bit the bullet and carried it to the repair shop. They checked it out and told me that I had put too much freon in it. When I got it back it was a little better, but after talking with others and reading on this form I had decided to tough it out the rest of the summer and get a new compressor this winter. I was reading through this post today about the MAX A/C. I read your reply about the vacum lines, and thought I'd just go and check it out. I found the line under the glove box where you had said, but there was no leak. Now, here comes the embarrassing part. On the intake vent much to my suprise, I found a "Taco Bell" wrapper embedded in the intake vent. I pulled it out, and it started blowing papers off the seats at about 40 degress. I guess the guy that owned it before me wasn't much for trash cans. Kwikkordead thanks again, and if you ever find yourself down in San Antonio, I like to take you for a ride in my "cool" truck.

 

Hahaha. That's great! It's the simple things like that, that will give the biggest laugh. Thank you.

 

where is the intake vent you found the wrapper in?

 

Look under the glovebox. The intake vent is in the uper right-hand corner.

 

tks ill check it out

norstar

 

Thank all of you so very much,,,its fixed,, in looking for my own wrapper I saw a white vacum hose with a 90% bend at the end just hanging their, soon after I spotted a place to plug it into. I had to remove the glove box, to get at it but its all "cool" now!

thanks for all the help
(cool in NC)
NORSTAR

 

i had the same problem, for me it was the vaccume pump for the ac, the diesels dont use the engine for vaccume so they have a seperate little electric pump. after changing that everything worked fine for me