05 Dakota,4.7L.When I turn off the heater fan/AC,clicking sound under dash.Also happens when control knob from defrost to floor/windshield.Blend door? Vacuum or electric operated And how to fix ?

SOURCE: Heater/AC only works thru defroster vents on '98 Contour

you prob have a vac leak on the back of the intake. good luck

Bill

• 424 Answers
• Posted on Jun 10, 2009

SOURCE: Vacuum Controlled A/C Blend Door Issues

Check the white vacuum hose going to your recirculation vacuum motor under the hood to the right side of the fire wall. It runs inside a wiring harness. The hose will get brittle and break apart. Start there it is the most common vacuum leak on a ford truck.I hope this helps.

SOURCE: air only blows on defrost (windshield)

Check vacuum lines on firewall for leak, check all vacuum lines if one on fire wall is ok , doors work off vacuum

Bill

• 424 Answers
• Posted on Nov 09, 2009

SOURCE: 2005 Ford Focus ZX4 AC switch in dash does not

Sounds like there is a foreign object in the heater case. The only way to reapair it is to remove the object by possibly removing the heater case.

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SOURCE: heater/AC vent option knob produces knocking sound

If I am reading correctly you are hearing the vent doors moving to redirect the airflow to the vents you choose. This is normal and can be more noticeable if the blower fan is on, putting air pressure against the doors.