I have a 2008 F-350 6.4L turbo diesel and I am having problems with the a/c. It is cold enough (around 50 degrees) but the air doesn't blow very strong. On AC Max and the fan on 4 with all vents open I get about 6mph air speed compared to other similar trucks on the same settings that get over 15mph. What can I do to fix this problem?

 

Is there a significant difference between MAX and normal AC?

If so and it's the MAX that's weak, check for junk sucked up into the recirculate door vent behind the glove box. Plastic bags or wrappers are common.

 

It is both setting that are pretty weak but I will check the intake anyway.

 

I am having the same problem with my '01. Help to narrow down the cause by the symptom....
1.) Is there fan speed difference between HI on A/C an HI on MAX A/C?
2.) Pull out your blower motor, Looking straight towards the rear, the grid you see is the re-circulaitng cabin air intake everyones talking about. Is it clear?
3.) Using a flashlight and a mirror, check out the evaporator core. you will see a pocket to the inside of the truck in the blower cavity right where the squirrel cace sits botttom right, looking aft. Is there blockage there? May report there being dirt/debris blocking theirs.
4.) Do a visual on the resistor package. its on the front of the vent box between the blower motor cavity and the evaporator. Sometimes these get rusted.
5.) If this all looks good, your in my boat! Time to start checking voltage drops with the fan circuit.

My '05 excursion seemed to blow with 2x the force my '01 does. Good luck!

Doug