Heater/ac issue
Thread Starter
|
Senior User
Joined: Dec 2011
Posts: 221
Likes: 0
From: Needville (Houston) Texas
Heater/ac issue
I am having a bit of trouble with my heater/ac mode switch I believe. No matter what position i put the switch on it only blows through the defroster vents. The only other position that works is off. When it is on off then it doesn't blow out of any vents. Does this sound like the mode switch itself or an actuator or something like that inside the system? How tough is it to remove the dash to get to this switch if it is just the switch?
Elder User
Joined: Mar 2008
Posts: 626
Likes: 0
From: Ontario, CA
I'm guessing (MY BAD) you have 4WD; it is the Electronic Shift On the Fly hubs. They are vacuum operated. when they start leaking, heater/AC defaults to defrost. If you don't have 4WD, time to look at another vacuum line I guess...
Thread Starter
|
Senior User
Joined: Dec 2011
Posts: 221
Likes: 0
From: Needville (Houston) Texas
ok. No, mine is a 2wd. When this happened with my jeep it was just the switch but I will start looking at a vacuum leak i guess. It's not that big of a deal except my feet are cold!
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Don's got you on the right (vacuum leak) track.
The Federally-mandated "default" failure mode is Defrost. That's all the Feds consider to be absolutely necessary.
Even though you're freezing, you legally have to be able to see out the windows!
Pop
The Federally-mandated "default" failure mode is Defrost. That's all the Feds consider to be absolutely necessary.
Even though you're freezing, you legally have to be able to see out the windows!
Pop
Thread Starter
|
Senior User
Joined: Dec 2011
Posts: 221
Likes: 0
From: Needville (Houston) Texas
Trending Topics
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
First, make sure your vacuum pump runs. That's where you get your vacuum, as diesels don't have any intake manifold vacuum. The truck still needs vacuum to run the HVAC controls and baffle servos..
Pop
Pop
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
More Turbo
Joined: Apr 2009
Posts: 712
Likes: 1
When I first bought my truck it had this issue found out that the vaccum pump was n/g. replaced it and havent had any issues. If you need one 1aauto has one with lifetime warranty. I had one fail, called them up and they sent me a new one no questions asked.
hope this helps,
-AJ
hope this helps,
-AJ
Thread Starter
|
Senior User
Joined: Dec 2011
Posts: 221
Likes: 0
From: Needville (Houston) Texas
It was a fuse to te vacuum pump. The different part is that you couldn't tell the fuse was broken from looking at it. An ohm meter on te fuse confirmed the circuit was broken and a new fuse got it going.
Thread
Thread Starter
Forum
Replies
Last Post
deemac
1999 - 2003 7.3L Power Stroke Diesel
11
Feb 13, 2012 05:18 PM
78bigunns
1973 - 1979 F-100 & Larger F-Series Trucks
6
Jul 10, 2011 09:28 PM