'96 Exploder HVAC

 
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x-post to rec.autos.tech,alt.trucks.ford

4.0/ AT, 85K, CC recall performed

Symptom: Diverter valve remains open and does not respond to heat
control potentiometer.

It closes as it should when the HVAC is set to "Max AC" or "Off" per
the vacuum map I got from the Advance site.
https://picasaweb.google.com/lh/photo/tY0XZzuZLxnsuuvyBVTfSf-Nmmm7sXsX9_b_TEXLWf0?feat=directlink

http://tinyurl.com/7agwg7x

Parts replaced: (FoMoCo): (1) Diverter valve  (2) Potentiometer.

I'm out of ideas.
 -----

- gpsman

Re: '96 Exploder HVAC


summat doesn't make sense.  How does the diverter get affected by the
potentiometer?  Is there an electrical connection between the pot and
the diverter valve, or is there supposed to be variable vacuum applied
to the diverter by the control head?  Direction of additional
troubleshooting would depend on the answer to that question, and I
can't tell from the vacuum diagram.

nate

Re: '96 Exploder HVAC


https://picasaweb.google.com/lh/photo/tY0XZzuZLxnsuuvyBVTfSf-Nmmm7sXsX9_b_TEXLWf0?feat=directlink

The valve is working properly. Vacuum is applied when the heater control
knob is turned to MAX A/C and OFF. Otherwise the valve is held open by a
spring and coolant flows through the heater core.

Temperature is controlled by the temperature control knob, what you are
calling the potentiometer, which is connected to the blend door motor.
The blend door motor is electrical. The position of the blend door
determines how much air flows through the heater core, vs how much air
flows over the A/C evaporator coil.
--
David Chamberlain


Re: '96 Exploder HVAC

On Jan 4, 10:54=A0pm, David Chamberlain

Ah!  I've let myself be led astray by what I thought I knew... again.

Thinking about it now, I don't know how I suspected variable vacuum
would be applied and maintained to control the coolant flowing through
the core.

A little more research suggests 15 years was better than many people
get from these blend doors/motors.

Just for anyone else who may come across this with the same issue/s, I
made a temporary solution last summer by figuring a couple wire ties
to hold the valve closed.  It took 2, 1 for the valve and 1 to hold
that tie in place.

Thanks a million!
 -----

- gpsman

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