Jesse Stafford
Member
I can only get air to blow out of the vents on my 02 Sport Trac. Anyone else have this before? I was told it might be vacuum line, but where?? Thanks
Defrost only?? No air out of vents
- Thread starter Jesse Stafford
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Kevin Palmer
Well-Known Member
This is what happens when you lose the vacuum control. By that, if the vacuum line falls off the connection, you will get ONLY defrost. It is set up this way for safety reasons, you will ALWAYS be able to defrost your windshield.
There are two common places the hose falls off. The passengers floor above the feet area and the connection from the engine to the fire wall...
There are two common places the hose falls off. The passengers floor above the feet area and the connection from the engine to the fire wall...
J B 2
Member
jesnamy,
The connection mentioned above the passenger foot area can easily be viewed by dropping the glove box out of the way (there is a plastic tab on the each side of the glove box, they are the stops that prevent the glove box from opening too far, bend these inward and lower the glove box), look to the upper left through the opening, this connection has 6 or so tiny vacuum lines that all form into a plug, make sure that it is plugged together tightly. You can uplugged it and with the engine running verify that you have vacuum by plugging them with your fingers, I think the bottom ports are the ones that bring vacuum from the engine.
Another possibility is the small vacuum motor that actuates the damper door that directs air to the vent panel, this vacuum motor is located above the brake/gas pedal area. It is tough to see but if you get your head under the dash and look up you will see a small round silver object with a vacuum line running to it and linkage connected to a white plastic arm, not the one next to the transmission hump but farther towards the e-brake area and higher (tough to see), listen for a tiny air leak, sometimes the diaphrams crack and won't allow the vacuum to pull the damper. While you are upside down have a helper start the vehicle and move the controls from vent / AC to defrost and watch the linkage to see if it tries to move, check the linkage to make sure it is hooked up and unplug the line to see if you have vacuum to this motor while the engine is running and the heater is set to AC or vent.
Such a minor piece but hard to replace.
A third less likely possibility is the connections on the back of the heater controls - these can be easily viewed if you pull your radio from the dash (you will need the stereo removal tools for this). Although not likely these heater controls have failed and this will cause the same problem.
The connection mentioned above the passenger foot area can easily be viewed by dropping the glove box out of the way (there is a plastic tab on the each side of the glove box, they are the stops that prevent the glove box from opening too far, bend these inward and lower the glove box), look to the upper left through the opening, this connection has 6 or so tiny vacuum lines that all form into a plug, make sure that it is plugged together tightly. You can uplugged it and with the engine running verify that you have vacuum by plugging them with your fingers, I think the bottom ports are the ones that bring vacuum from the engine.
Another possibility is the small vacuum motor that actuates the damper door that directs air to the vent panel, this vacuum motor is located above the brake/gas pedal area. It is tough to see but if you get your head under the dash and look up you will see a small round silver object with a vacuum line running to it and linkage connected to a white plastic arm, not the one next to the transmission hump but farther towards the e-brake area and higher (tough to see), listen for a tiny air leak, sometimes the diaphrams crack and won't allow the vacuum to pull the damper. While you are upside down have a helper start the vehicle and move the controls from vent / AC to defrost and watch the linkage to see if it tries to move, check the linkage to make sure it is hooked up and unplug the line to see if you have vacuum to this motor while the engine is running and the heater is set to AC or vent.
Such a minor piece but hard to replace.
A third less likely possibility is the connections on the back of the heater controls - these can be easily viewed if you pull your radio from the dash (you will need the stereo removal tools for this). Although not likely these heater controls have failed and this will cause the same problem.
Dan Long
Well-Known Member
This is happening to me while the motor is under load.. on moderate to hard acceleration, or accelerating up hills my A/C will often switch from the dash vents to the defroster vents, then switch back when I ease off the gas. Ideas?
EddieS'04
In Memoriam 1950-2022
Dan,,, you may have a small vaccum leak. Or look and see under the hood. The vaccum line from firewall to source for a small check valve. I dont know if the trac Has one outside or inside. If it is bad you will loose vaccum controls when accelerating. If you cant find it you can add one anyway. I had to do this on a dodge doing the same thing awhile back.
edit; you can get a generic vaccum check valve almost anywhere. Make shure of the tubing size.
edit; you can get a generic vaccum check valve almost anywhere. Make shure of the tubing size.
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- What engine do you have?
- V8 engine
- What year is your Sport Trac?
- 2010
- What Generation is your Sport Trac?
- 2n Gen Owner
Check the vacuum ball located inside the Passenger fender, and the hoses going to it..
Todd Z
Todd Z
Kevin Palmer
Well-Known Member
Dan, I will agree with Todd as afar as the vacuum ball having a leak in it as far as your issue goes. It is designed to give vacuum to controls when the engine is under higher RPM's as this is the least amount of vacuum available until the engine RPM's decrease or the vacuum builds up.
Dan Long
Well-Known Member
Thanks guys, I'll check it out. I knew that engine vacuum can be very low to none under load, but wasn't sure what was done to overcome that in our trucks, as my 4 door Ex has never had that problem.
