AC shifting to vent
Thread Starter
|
Senior User
Joined: Mar 2004
Posts: 256
Likes: 0
From: Austin, Tx
AC shifting to vent
Does anyone with a 2002 or so model have any problem with their A/C where it shifts from the vents to the defrost section then comes back by itself? I noticed this on my 02 at around 50K miles and opened up the AC controls and changed the solenoids around and the problem went away for a while and now its back. My truck is the lariat and is digital controlled. Does anyone know a permanent fix for this?
Post Fiend
Joined: Feb 2003
Posts: 6,940
Likes: 2
From: Eastern WA
It really doesn't matter what model of Ford it is, they shift to defrost by default when there is low/no vaccum. Look to make sure you have no loose/damaged vaccum fittings/connections. They also use a vaccum reservoir, make sure it's undamaged (potential leak source). Also, there is a check valve in the system to maintain vaccum when you put your foot into it. Sometimes the check valve is integrated with the vaccum reservoir. You need to check for proper operation of the check valve. I'm not really familiar with electronic systems, but it would only stand to reason that, for safety reasons, if there were a vaccum leak issue it will default to defrost. I've also seen people talk about ways to pull codes from these systems. I wouldn't worry about that until you've made sure the vaccum lines etc are in good order.
Last edited by CowboyBilly9Mile; Oct 16, 2005 at 07:59 AM.
Thread Starter
|
Senior User
Joined: Mar 2004
Posts: 256
Likes: 0
From: Austin, Tx
Thanks Cowboy,
Will try and locate a vacuum leak. The weird thing about it though is that as I mentioned above, the problem was gone for a while after shifting the solenoids behind the control panel. Hey now that I remember, the solenoids did have tiny orings that control the vacuum. Maybe one got dirty. The first time I did try to find a vac leak and could not find one on the lines.
Will try and locate a vacuum leak. The weird thing about it though is that as I mentioned above, the problem was gone for a while after shifting the solenoids behind the control panel. Hey now that I remember, the solenoids did have tiny orings that control the vacuum. Maybe one got dirty. The first time I did try to find a vac leak and could not find one on the lines.
