Cable on blend door.

[Denisefwd93]

That's as far as I got I looked in there and I see there's a cable instead of a potentiometer hopefully I'll have things apart in the next couple days I'm sure I'll find rats nests, on assuming I probably bypass the hot water coil for summer I could put it through way valve in your and get fancy under the hood like I had on my boat hot water heater bypass.
Just one question, do the heater hoses have to circulate or can they be pinched off so there is no circulation?

 

[alwaysFlOoReD]

I don't know on the circulation but I just use a piece of copper tube and hose clamps and join the ends together if my heater core leaks.

 

[Denisefwd93]

Well, the AC unit has been removed off the firewall! No squirrels in the "squirrel cage" no rats, lots and lots of debris grass and leaves from the critters, not one trace of oil on the evaporator but it needed to come apart anyway. the blend door is definitely is not sealing properly, not looking forward to taking the dash apart and addition to everything else we'll probably just bypass the heater core until winter.

 

[RonD]

Yes, 1993 needs heater hoses to be connected, via a loop or the heater core.
You can just take the intake heater hose down to the water pumps heater hose port, or visa versa, so no splice just one hose

The heater core is the by pass for the water pump.
If it is blocked your temp gauge will randomly go up past 1/2 then back down, truly random, lol, uphill down hill, hot day cold day, just goes up and down

 

[Denisefwd93]

Thanks Ron!
So the cables for function and temperature are on the top of the heater box behind the glove compartment door which is easy to tilt down out of the way. Cables are easy to adjust, just a clip that holds the cable jacket in place that is the "adjustment" it's pretty low-tech. I did adjust temperature setting which controls blend door I'm still not sure the blend door is closed 100%

The function cable adjustment seems more critical, need to play with that.

 

[RonD]

Yes, Blend door(temp only) is cable operated thru 1994, 1995 saw start of the electric Blend door, and problems associated with that type of motor.

Cable is adjustable, Blend door directs air from the fan thru the heater core(HOT) or closes off the heater core(COLD), or you can blend air temp in between the two
It does have sticky foam strips as a seal around the edges, and it rots over time so seal may not be perfect

The "Functions", Vent controls, are all vacuum operated, from 1983 to 2012 Rangers

There are 2 main vacuum "motors", for air direction to Floor, Panel, or Defrost
No vacuum = Defrost, it is the default
So if vent direction control doesn't work but you do get good air flow from Defrost vent then you have no vacuum at the control panel.
Vacuum for this comes from a Vacuum reservoir, in 1993 it should be a black cylinder on top of heater box in engine bay.
Reservoir is connected to intake manifold with a Check Valve inline, so always has vacuum available, like power brake booster.
If you had air blowing out of the panel vents and then accelerated, and air flow moved to Defrost vent, that means vacuum reservoir is not holding vacuum in reserve, small leak in reservoir tank usually.


There is a 3rd vacuum motor for a Fresh Air Vent, it can be closed for MAX AC setting, so AC is cooling already cooled air inside the cab, instead of HOT air from outside

 

[Denisefwd93]

Hmm ok but there is another cable on the max, panel, floor etc , control lever

there was residual vacuum still on the little Reservoir when we took it apart, I just had heat coming through on the panel setting and noticed that the shutter door was not closing,

 

[RonD]

Two cables, could be, the vent control is a slider, my '88, '92, and '94 had/have vacuum lines but never needed to pull out the control to look if there was a 2nd cable as well

 

[Denisefwd93]

Well I found out how easy it is to get the heater core out that takes about 20 minutes! There is a vacuum motor on the far right which I assume is for the defrost or cabin intake.

 

[RonD]

Fresh air intake vacuum motor on far right.

Yes, 4 screws and 2 hose clamps, heater core is out