I have an 06 Grand Marquis Limited that the ac is blowing from the defrost. I’ve learned it’s an issue with the climate control unit. I’ve pulled on from an 05 Grand Marquis. Mine is like a black box(digital) and the 05 is just the face. Will this work??
Check the connections on the back. If they are not the same, you may not use it.
I have to be skeptical if the electrical connectors on the digital HVAC Control Head are the same as the analog (knob) Control Head.
.... But maybe.
Check the wiring connectors.
However, you could figure out where to connect the vacuum hoses to the "Vacuum motors" pretty easily between the 2 units even if the locations on their manifolds aren't the same.
incidentally, have you checked if the Control Head is getting vacuum from the underhood vacuum reservoir?
Let's look at that unit you're considering replacing and the vacuum line manifold connections and their color codes to the back of your HVAC Control Head, shall we?
So in the above diagram, #1 is the Defrost/Panel vent vacuum motor.
#14 is the Floor Vent vacuum motor.
#9 is the Fresh Air/Recirculate vacuum motor.
Notice vacuum Motor #14 has to close the Floor vent for the blower's air to reach the #1 Defrost/Panel vent door to make that selection.
Here's the color codes of those vacuum lines connected to the back of that HVAC Control Head's manifold:
It will look like this back there:
You have 3 vacuum motors with 4 vacuum lines going to them. (notice #1 vacuum motor has 2 vacuum lines going to it)
The A/C / Heat actuator door (#14) isn't controlled by vacuum. It's controlled by an electric actuator motor.
So, if you aren't getting vacuum at that Black vacuum line, your issue is with the underhood vacuum reservoir or the Black vacuum line going to the control head.
Ideally you'd use a vacuum gauge but I don't see why using your finger wouldn't work good enough.
Pull off the Black line and feel if vacuum is being pulled through it.
If it is, you can do the same thing, Reconnect it and feel for vacuum at either the individual HVAC control head manifold ports or at the vacuum motors as you cycle the vent controls.
if you test at the motors, you can eliminate both the control head and the vacuum lines going to them all at once. (maybe a broken vacuum motor)
If you have vacuum going into the HVAC control head through the Black vacuum line, and you don't have vacuum at each of the vacuum motor ports of the control head vacuum manifold as you cycle their individual (vent door) vacuum control motors, then the control head is malfunctioning
