-
Welcome Visitor! Please take a few seconds and Register
for our forum. Even if you don't want to post, you can still 'Like' and react to posts.
A/C vent control issue
- Thread starter Dandydon
- Start date
- Joined
- Jun 2, 2012
- Messages
- 25,363
- Reaction score
- 8,367
- Points
- 113
- Location
- canada
- Vehicle Year
- 1994
- Make / Model
- Ford
- Transmission
- Manual
Welcome to TRS 
Vent controls are operated by vacuum "motors"
Defrost is the "default" vent selection, i.e. no vacuum = Defrost only
The Vacuum it uses comes from the intake manifold, like power brake assist uses.
For vent control this vacuum is stored in the vacuum reservoir, a black plastic ball, usually located down low at the front of the engine bay passenger side, often best seen from under the truck.
From the vacuum reservoir there will be a black plastic vacuum line, looks like a wire, that runs into the firewall on passenger side, next to blower motor, you will see a grey plastic vacuum line with it, thats for Heater hose valve in engine bay.
The Black plastic vacuum line is often melted over time by exhaust heat so you loose vacuum in the cab, or it simply gets brittle and breaks
This line can be repair with regular rubber vacuum hose, the hard plastic hoses are just cheaper for Ford to use.
No clamps are needed since it is "vacuum" inside, so it "pulls" connection tighter it doesn't try to push it off, just get correct size rubber line to slide over the hard plastic line, cut a section out to take with you to auto parts store.
So I would start by first finding that black plastic line from firewall to reservoir and make sure it is OK
The Vacuum reservoirs have been know to crack and leak just from age, and even minor front end collisions can damage these.
The reservoir gets vacuum from the intake manifold and this line could have been unplugged after engine work, so once you have found the reservoir trace its other line back up to intake manifold
Vent controls are operated by vacuum "motors"
Defrost is the "default" vent selection, i.e. no vacuum = Defrost only
The Vacuum it uses comes from the intake manifold, like power brake assist uses.
For vent control this vacuum is stored in the vacuum reservoir, a black plastic ball, usually located down low at the front of the engine bay passenger side, often best seen from under the truck.
From the vacuum reservoir there will be a black plastic vacuum line, looks like a wire, that runs into the firewall on passenger side, next to blower motor, you will see a grey plastic vacuum line with it, thats for Heater hose valve in engine bay.
The Black plastic vacuum line is often melted over time by exhaust heat so you loose vacuum in the cab, or it simply gets brittle and breaks
This line can be repair with regular rubber vacuum hose, the hard plastic hoses are just cheaper for Ford to use.
No clamps are needed since it is "vacuum" inside, so it "pulls" connection tighter it doesn't try to push it off, just get correct size rubber line to slide over the hard plastic line, cut a section out to take with you to auto parts store.
So I would start by first finding that black plastic line from firewall to reservoir and make sure it is OK
The Vacuum reservoirs have been know to crack and leak just from age, and even minor front end collisions can damage these.
The reservoir gets vacuum from the intake manifold and this line could have been unplugged after engine work, so once you have found the reservoir trace its other line back up to intake manifold
Last edited:
Stainless10FP
New Member
- Joined
- Jul 24, 2018
- Messages
- 6
- Reaction score
- 0
- Points
- 1
- Vehicle Year
- 2003
- Make / Model
- Ford
- Transmission
- Automatic
Have you checked the actual switch itself? I had this same issue and it turns out the housing of the switch itself had cracked and became a major vacuum leak in the dash. I replaced the switch and all was good. 2 weeks later the new one cracked again in the exact same location. New switch arrives tomorrow but I need to find the reason it’s breaking before I put another one in.
Sponsored Ad
Sponsored Ad
Staff online
-
Jim OaksJust some guy with a website
Member & Vendor Upgrades
For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.
Latest posts
-
1993 Ford Ranger Blue RWD Manual Splash
- Latest: MasonDaniel7
-
-
-
-
-
-
-
Truck of The Month
Shran
April Truck of The Month
Recently Featured
Follow TRS On Instagram
TRS Events
25th Anniversary Sponsors
Check Out The TRS Store
Sponsored Ad
Sponsored Ad
Sponsored Ad
Amazon Deals
