Defroster default
 

'03 F150 4.6l. When towing travel trailer (3300#) AC goes to defroster most of the time. Understand thats the default, but would like to change default to vents. Any way to do this?

fix the vacuum leak in your system

If you want to tie 3 tie wires to the arm of the actuator are under the dash at the end of the vac line, you can make it blow through the vents all the time. Better to fix your vacuum leak as that is the problem. Check the vacuum line running in from the passager side of the truck firewall and into the back of the dash. See if that line is attached correctly from beginning to end. At the same time see if your other vac lines running to the canister behind the battery or under the passager wheel well are not leaking. Once you have checked those and made repairs or they are good if you have the push button controls for AC/Heat it is different. On the push-button controls, you need to remove the unit and break it down to replace the o rings inside the unit. The unit has a vac line housing running to it, unplug it and you remove the cover to get to the cylinders inside that have a spring and o rings. Put vaseline or a substance like white lube grease on them when installing new o rings (match at any auto parts store) and then put the unit back together again. In one of these the o rings were known to be some, not all the wrong type from Ford 1998- 2008 parts supply people.