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Discussion Starter · #1 · (Edited)
No defrost, I know why but not where to get part(O.K so I was way off, new questions)

So I propped open the blend door(vacuum operated and not working) to see if I'd get any more flow from the defroster vents and still no airflow so I took out my glove box to get a good look. Well I wasn't expecting to look through and see my blower motor:doh0715:. I believe what I'm missing is called the air distribution box? Am I junkyard bound? Anyone have a picture of what it should look like on an '85 that had AC, are they all the same? Will I need to pull the heater core or anything else to get it installed?

Any help or pics would be greatly appreciated.
 

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Discussion Starter · #5 ·
Went to the JY and came to the realization that I have no idea what I'm looking at here. When I propped open the vacuum motor against the firewall on the passenger side and could see the fan, I thought I was missing some sort of cover for it. Imagine my surprise when they were all like that.

O.K. so on the heater core only diagram, the floor/defrost canister is horizontal(as it would sit in the truck) but in the ventilation diagram it appears to be vertical and the panel door canister is horizontal. Am I looking at that right?

On my truck, when I push in the arm on the vertical canister(which is closer to the dash center and higher), I do get a some airflow through the floor ducts but I couldn't do anything to it to get airflow from the defroster. I also didn't seem get any change when manipulating the horizontal(further right and lower) canister.

How exactly do the vacuum motors/canisters work? Do they work in conjunction or individually to direct flow?

What exactly is the function of the door directly behind the blower fan? It has foam on it, is it simply a filter?

Sorry for the quantity of questions, I've never really done any work with the heating/cooling systems of the cab. Frankly, I'd be happy if I could just rig it to always be on defrost. I could care less about the floor and vents at this point.
 

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yo, Here is the bottom line;
Off- Vacuum is applied to Outside Recirc Door Vac Motor, closing that door to outside Air.

Normal A/C - Outside-Recirc Door is open to outside air. The panel door directs air to the instr panel registers.
The Temperature Control Lever moves a cable connected toTemp Blend Door that mixes heated & un-heated air

In Defrost Mode; with No vacuum to any vacuum "motor" (cannisters looking things), air Flows to Defroster outlets (& air compr clutch is engergized)

Vent - Outside-Recirc Door is open to outside air, as in Normal A/C.
Vacuum is applied to the Panel Door Vacuum Motor, letting air flow only to the instr panel registers.
In the same way, the defroster outlets are closed by the Floor/Defrost Vacuum Motor.

Floor - The Outside-Recirc Door is Open to outside air.
With No Vacuum at the Panel Door Vacuum Motor.
The Panel Door directs air to the floor outlets.

Mix - Vacuum is applied only to Port A of the Floor/Defrost Vacuum Motor positioning the Floor/Defrost Door at mid-position.
Air Flow is split between the floor & windshield.
There is no vac at the Panel Door Vacuum Motor.
This closes the instr. panel registers

So, am thinking that the Floor-Defrost Door is stuck...So. to test, pull & cap or pinch off vac line to the Floor-Def Vac Motor to see if door moves to the Full Defrost position (by feeling air flow).

btw, hear any hissing that indicates a vac leak under isntr panel or in those door areas and control panel?


or much less likely, vac is going to floor bec the floor-def door is stuck or A/C- Heater Function Selector Vacuum Valve (in Chris's diagram below) is messed up
Now, for what is what; my pal, Chris B posted this once on his site;


and a pic of the Blend Door/Foam in an 83..same as your yr; by Steve83

"This is looking rearward over the R wheelwell with the evaporator cover removed beside the R exhaust manifold."

I'll post this now just in case we lose power.
 

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yo, ok, that got thru!

Next is to ID the Doors.
A control cable is attached ONLY to da temperature blend door. So that makes it ez to id.

Since I don't have any one w/ your year (range) around here anymore; look at this pic by Steve83

"After lowering the column, removing the big Aluminum casting, unbolting the 2 large connectors under the brake booster & releasing them from the firewall, the 3 connectors in the R kick, & the green ground screw, there are four 7mm (T15) screws along the w/s, an 8mm (5/16") at the R end, and two 8mm screws at the brace bars above the tunnel, and the dash flops onto the floor. Then the vacuum lines, HVAC cables, & antenna cable can be released, allowing the dash to come out"

Can you match this to the other diagram by Steve?

combined w/ your Q..."O.K. so on the heater core only diagram, the floor/defrost canister is horizontal(as it would sit in the truck) but in the ventilation diagram it appears to be vertical and the panel door canister is horizontal. Am I looking at that right?"
Go with the horizontal position.. I think from memory, but don't count on my mem today, ok?
 

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Discussion Starter · #8 ·
That last pick is a different set up than what I've got, but it gives me a better idea of how things are situated. I think the first thing I'll do it try pinching off the vacuum lines and see if I can get any change. So far the only change I've gotten was when I pressed in on the vertical motor, I got air through the floor vents. That motor only has one vacuum line though, so it shouldn't be the defro/floor motor. The horizontal one does have to lines to it. Gonna have to wait till Sunday, I'm to exhausted to do anything tonight.

I don't hear anything to indicate a leak, where does the system draw vacuum from?

What's up with your eyesight? Nothing serious I hope.

Thanks again.
 

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yo,
ok, That looks luke the main vac line..
Main vac source comes from engine intake manifold, usually a tree and then onto the vac tank w/a check valve in the ckt; th
I asked about vac leaks just fir the heck of it to clear my mind of any previous owner or shop's "work-arounds".



Vacuum Hose Harness Pic in 80-96; "...80-96 similar, except 87-early 88 w/factory air; The 80-86 vacuum tank is a plastic ball on the R wheelwell..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

This is probably similar, in 92-96; & since we don't have anyone else chiming in w/a Ford EVTM /Service Manual,
Black = from engine source (intake man.) to vacuum check valve & to vacuum reservoir tank & to Control Panel;
White = actuates the Outside/Recirc air door two-position vacuum control motor;
Blue = Mix (actuates the FLOOR/PANEL air door two-position vacuum control motor);
Red = Floor Flow
& Yellow = Panel, (actuate the FLOOR/DEFROST vacuum control motor).


Vacuum Tank (plastic ball type) Location pic in mid 80s; the "right side" (passenger) near the EEC Test Connectors
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
&
Vacuum Tank for AC (plastic ball type) Location & Carbon Cannister (Charcoal, Vapor, Evaporative Emission (EVAP) & Vacuum Hose Routing Video in an 86 5.0
Source: by JKossarides ("The Bronco", Jean) at SuperMotors.net



I have the typical retina flashing prob, but it's clearing up, slowly, thanks!
 

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Discussion Starter · #11 ·
Fantastic, O.K. so this thing doesn't have any of that vacuum equipment on it. Maybe not so fantastic actually but I'm sure that's the issue.

So the that vacuum distribution block is still on the firewall but the plastic tank is long gone. All I should need to do is get that plastic ball and run the lines.

Thanks so much, I'll hit the junkyard and post back with the results.
 

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yo

wow! no vac tank! figures..

GL!
 
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