Ford Power Stroke Nation banner

Only defrost

5K views 23 replies 15 participants last post by  powerking3300 
#1 ·
So i threw my A/C on today and now only air is comming out of the defrost vents. What causes this? I have never heard of this nor had this happen so i am totally in the dark
 
#4 ·
Also a vacuum line that runs behind the dryer in the engine compartment that likes to break, crack, rub through. It is black in color. Easy fix if it is, is to cut away the bad section and put some rubber vacuum line on it.
 
#5 ·
get out ur hand held vacum pump and start checking lines, yellow, blue, red. The black one is ur main vacum, white goes to engine compartment cylinder to control atmosphere air.
 
#10 ·
:whs:
 
#12 · (Edited)
check for source vacuum on the black hose. If you have vacuum on that check the red hose going to the vacuum control motor. No vacuum on black then its not coming from the source(vac pump or cracked lines). No vac at the red suspect failing control head. And if vac is good all the way to red at the control motor suspect failed motor.
 
#18 ·
what fuse was it mines doin the same thing
 
#22 ·
Well, the easy way is to use a test light. If it lights when touching both sides its good. It you use a meter when removed it should show around 0 ohms of resistance. Most people check them in the truck. Turn the truck on and use a test lamp to check both sides of the fuse. Both sides light up you have a good fuse, only one side lights up you have a bad fuse, no light lights up, no power to fuse for some reason. Looking at it is not good enough. The break in the fuse can sometimes be small enough to miss at a quick glance
 
#23 ·


Or an even better way (sometimes they are not so obvious), is to place one probe from a multimeter on each leg of the fuse. A good fuse will show zero ohms (short), a bad fuse will show infinity (open).
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top