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Chuck
Chuck, ASE Certified Technician
Category: Ford
Satisfied Customers: 2100
Experience:  33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance
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I have a 2003 Ford, F-150. With a temp. control system. When

Customer Question

I have a 2003 Ford, F-150.  With a temp. control system.  When the a/c or heater is on, the air will only blow out of the windshield deforster area.  It will not blow out of the panel or floor vents.  When this first started, it seam like a vacuum leak.  When you speed-up, the air came out of the deforster and when you back-off the gas pedal, it would come out the vents.  This continued for a while, but now it only comes out of the deforster, no matter how fast or slow you go.  Has this been a problem with this model?  What & where do I need to look to correct this problem?  Is it electrical or vacuum problem?Thank You,  Richard M. Hughes E-mail:[email protected] Please respond.
Submitted: 6 years ago.
Category: Ford
Expert:  Chuck replied 6 years ago.

Richard this is a vacuum leak.The default position for no vacuum is defrost.

 

On this vehicle the vacuum reservoir is located behind the battery.Here is a pic of it.

 

graphic

 

You have to remove the battery and battery tray to remove it. There will be a vacuum line coming from the intake manifold to it and one going from it to the inside of the truck. Maybe one of the lines are broken and have come un-done.

 

 

Customer: replied 6 years ago.
I'll check this out tomorrow & get right back with you. Hopefully, this will correct the problem & I will accept your answer then. Thank You!
Expert:  Chuck replied 6 years ago.
Sounds good.
Customer: replied 6 years ago.

I replaced the vacuum line from the reservoir & the blue check valve, Ford part. I took a vacuum reading from the main line coming from the intake manifold (18 lbs.) The problem is still there. If I take the a/c controller out of dash, can I see the vacuum line running to it? How much of the dash do I have to take apart to get the temp. controller out? Do you have any pictures of the vacuum line coming inside the truck & where does it go? Do you have written procederes how the temp. controller comes out of the dash?

 

Thank You! Richard

Expert:  Chuck replied 6 years ago.

Yes you can see it.The black line is the supply line.

 

Here are the instructions on removing it,these are for the electronic controls

Detach the center instrument panel finish panel.

  1. Rotate the center instrument panel finish panel vents inward.
  2. Through the vent openings, grasp the center instrument panel finish panel and pull outward.
  3. Detach the center instrument panel finish panel

 

 

 

 

 

 

graphic

 

Disconnect the passenger air bag deactivation (PAD) switch electrical connector

 

 

 

graphic

 

If equipped, disconnect the 4WD control switch connector. Remove the center instrument panel finish panel

 

graphic

 

Remove the screws

 

graphic

 

Remove the EATC module.

  1. Disconnect the electrical connectors.
  2. Remove the nuts.
  3. Disconnect the vacuum harness connector and remove the EATC module

graphic

 

The manual controls are pretty much the same.

 

Here are the vacuum schematics

The first ones are the manual system

 

graphic

 

ItemPart NumberDescription
118A318Vacuum control motor, panel/defrost door
2-Panel/defrost door (full vacuum position)
3-Defrost airflow
4-Side window mister airflow
518B545Temperature blend door (full heat position)
619860A/C evaporator core
7-Air inlet duct door (full vacuum position)
8-Outside air inlet
918A318Vacuum control motor, air inlet door
10-Recirculated air inlet
1119805Blower motor
12-Vacuum to emission control
13-Vacuum from the engine intake manifold
14-A/C vacuum check valve (part of 19C828)
1519A566A/C vacuum reservoir tank and bracket
1619B888A/C-heater function selector switch
1718476Heater core
18-Panel/floor door (full vacuum position)
19-Floor airflow
2018A318Vacuum control motor, panel/floor door
21-Panel airflow

 

graphic

 

PortHose ColorFunction
1WhiteAir inlet door
2YellowPanel/floor door
3BlackVacuum source
4-Not used
5BluePanel/floor door
6RedPanel/defrost door

VACUUM APPLICATION CHART-MANUAL CLIMATE CONTROL

Switch PortColorFunctionFunction Selector Switch Position
MAX A/CA/CPNL/ VENTOFFPNL/ FLRFLOORFLR/ DEFDEF
1WhiteRecirc/ freshVNVNVVNVNVNVNV
2YellowFull floorNVNVNVVNVVNVNV
3BlackVacuum sourceVVVVVVVV
5BluePanel/ floorNVNVNVVVVVNV
6RedPanel/ defrostVVVNVVNVNVNV

V = Vacuum

NV = No Vacuum

 

 

 

Here are the ones for the electronic

 

graphic

 

ItemPart NumberDescription
118A318Vacuum control motor- panel/defrost door
2-Panel/defrost door (full vacuum position)
3-Defrost airflow
4-Side window demister airflow
518B545Temperature blend door (full heat position)
619860A/C evaporator core
7-Air inlet door (full vacuum position)
8-Outside air inlet
918A318Vacuum control motor- air inlet door
10-Recirculated air inlet
1119805Blower motor
12-Vacuum to emission control
13-Vacuum from the engine intake manifold
14-A/C vacuum check valve (part of 19C828)
1519A566A/C vacuum reservoir tank and bracket
1619980Electronic automatic temperature control module
1718476Heater core
18-Panel/floor door (full vacuum position)
19-Floor airflow
2018A318Vacuum control motor- panel/floor door
21-Panel airflow

 

 

 

graphic

ItemPart NumberDescription
1-Not used
2RedPanel/defrost door
3BluePanel/floor door
4BlackSource vacuum
5WhiteAir inlet door
6YellowPanel/floor door

Vacuum Applications Chart-Electronic Automatic Temperature Control

Switch PortColorFunctionManual Override Selector Buttons
OFFMAX A/CVENTPNL/ FLRFLOORFLR/ DEFDEF
2RedPanel/ defrostNVVVVNVNVNV
3BluePanel/floor (partial)NVNVNVVVVNV
4BlackSourceVVVVVVV
5WhiteOutside/ recircVVNVNVNVNVNV
6YellowFull floorNVNVNVNVVNVNV

V = vacuum

NV = no vacuum

 

 

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