I'm don't know what the problem is with my air conditioning system, need help. I have a 2001 ford F150 4x4, 1st question, Mode Selector Control the air conditioner is on, on all modes. Is this correct? you just can't have outside air on a nice day? 2. The air blows out the FLR. & DEF. on all mode settings. Could this be a switch problem or do I need to remove dash or the interior of the ac unit to resolve this issue? thx. in advance..

 

Is this a trailer AC question?

If not it sounds like the a stuck door on a divertor or a vacuum leak because having the floor/def setting is a default mode when there is no vacuum. It is rarely the switch as the switch is just a mechanical valve. Check the vacuum lines behind the switch and at the junction further behind the dash.
An extreme engine vacuum leak can cause this as well.

 

Thanks Colorado Osprey, It is for my 2001 Ford F150. I'll check it out by taking out the dash front. I took out the dash out once to replace the lights in the dash panel and when I unplugged the switches I don't remember seen a vacuum line, but I'll look around behind the dash. Could any of these line be under the hood?? thx..

 

Edgar, why did you post an AC question in the Towing forum? We do have a HVAC forum and a forum for general questions about 97-03's.

 

Those vacuum line connector (multiple color hoses) can be had from the passenger side behind the glove box, no need to remove the dash. The center section of dash around the temp control switches comes off, and then you can access the back of the temp control unit after removing 4 screws. No need to pull the entire dash out like you are replacing a heater core.

If you have to replace the control door actuator, then the dash has to come out. It would also be an excellent time to replace the heater core if you are that deep into it since you are already there.

 

Colorado Osprey, I've taken much of the dash off tring to trace the location of the 5 vacuum lines. There's a Black, red, orange, blue & off white from the back of the control unit. I've located both ends of the red, blue & orange and they are ok (not broken, craked or loose) I cant find the black or the white lines where they end up at. could they be under the hood? or are they all behind the ac unit? thanks for any help...

 

Edgar, so it only does this when your pulling your trailer

 

I take them apart at the connector and attach a hand vacuum pump like the one used for pressure bleeding brakes. I turn the fan motor on high and try the differrent lines to see if the differrent actuators are working. If they are working, it is not an actuator problem.... you will need to find where a vacuum leak is.
A vacuum leak if there is one could be anywhere. It could even be on the manifold brake booster line causing the vacuum to drop enough to not actuate one of the climate control actuators.

 

bigdad8214, it does it all the time. I bought the truck this way in february. I took out the most of the dash today and by the amount of dirt not dust in the vents its been like this for a few years. I started to look under the hood and found 1 line that was rubber 1/2 off and another one craked. I will start again tomorrow looking thru one at a time and fixing them. Does any one have a vacuum line diagram file so I can look thru it?

 

You will get a lot better help in the appropriate forum!

 

Edgar, I found this website that might help you out a lot. Just click the link and scroll threw some of the post, and if you don't find anything that helps you out...... well maybe post........

https://www.f150online.com/forums/hvac-69/

 

glc, is there a way to move my post or do I need to repost it?
Colorado Osprey & bigdad8214 is there only one air compresor that is used for all vacuum lines? Today when I was changeing the oil I noticed that the horn has a vacuum line to it I thought it was electric, when I honk it sounds like a toy horn I thought it was blown but it might be the compresor, how can I test the compressor?. thx..

 

Vacuum comes from the intake manifold, not a compressor.

 

First I would like to thank Colorado Osprey, bigdad8214 and glc for your help.
I findly found the two broken vacuum lines, patch them with a peace of black rubber hose and my A/C works perfect, Air findly comes out the dash vents.
glc next time I'll make sure I post in the right location..
Thanks again...