Hello all, I am new to this forum and this is my first post. I just purchased from my father his f150 2002 lariat. It has climate control and does not blow on max ac through the vent. If I push max ac I get the air conditioning out the defrost vents. If I select panl floor I get air conditioning out the floor and panl. If I select vent it blowns fine through the vent only but of course its not running the compressor when you push vent. any ideas? also,, the heat works so Im not thinking its the blend door. Will this truck have the blend door problems too?

 

any ideas??? my toes are cold

 

I am having the same problem with my 02 Screw. Seems that when you let off the gas it will blow like it is supposed too. Going on an overpass will put it back to the defrost. I actually tie wrapped the door open so it would stay in the dash area. The actuator is right there by the gas pedal. Now that it is cold I need my defrost at times so I had to remove the tie wrap. I think the culprit may be a leaking vaccuum line. I have heard those are hard to find.
There is a way to run a diagnostic on the AC system. To do the self test, push the FLOOR and OFF buttons at the same time followed by the AUTOMATIC button within 2 seconds. The codes are:
024,022 Blend door short
025 Blend door failure
031 AC sensor open circuit
030 AC sensor short circuit
041,043 AC temp. sensor open cir.
040,042 AC temp. sensor short cir.
050,052 AC solar radiation sensor cir. shorted

to exit the self test press the blue button to save the codes, press DEFROST to erase the codes.

Mine never showed any faults always 888 which means no codes in memory.
Hope this helps.

 

Sounds like you have a vacuum leak or a check-valve that may be bad. Check the vacuum lines under the hood.

 

I have heard to use a starter fluid around the vac. lines and when the engine revs, that will give you an idea of where the leak is at.
Also, where would I start to look for the check valve?
Thanks in advance.

 

i'm havin the same kinda problem, i get no vent action when i switch the dial, but if i switch the dail, then manually move the rod by the gas pedal, it has enuff vac to hold it open.

how much vacum should i be gettin?

thanx

 

My A/C blew out the panel until the engine was under load then it went to the defrost until the engine was unloaded. The problem was a cracked vacuum line coming off the bottom of a check valve between the battery box and the firewall. This line goes through the firewall. I put silicone tape around the crack...problem solved.

 

This is, by far, the most common reason for loss of control of the air outlet for the climate control system.

Steve

 

My 2001 Supercrew started acting funny this past week. I had the truck in the shop for Transmission service, and while there I had them go ahead and replace the battery. Since I got it back when I go up hill, when the truck starts to really pull the Air Conditioning moves from the vents to the defrost vents.

Would this be a similar issue? I haven't had the hood up - is it possible the battery pinched the hose?

Thanks for the info -

Mike

PS: Tomorrow evening I might go under the hood and check for a leak.

 

That is the exact same as mine. This is what I have found so far with the help of some of the guys on here. The vaccuum line runs along the firewall behind the battery. It has a "T" there. One line goes into the firewall and supplies the AC, the other one goes along side the battery and I haven't taken my battery out yet to track that one down. The one that goes into the firewall is hard to try and pull out, it is molded into the grommet that passes through the firewall. I was told that that area is wher it usually cracks. But since they replaced your battery you may check the one that runs along side it. Hope this helps, I have yet to fix mine. Let me know what you find.