Ack! My A/C is acting up in my 2001 Dodge Ram, I am beyond 36k miles &
I need some advice. It blows either hot air, or cold air...nothing or
not much in between. My compressor always kicks on. The hot air always
blows fine, however the cold air will sometimes blow hot...actually
about 50% of the time...and when it does blow cold it'll switch to
blowing hot usually within a couple minutes. Sometimes turning it off
& back on again will make it blow cold again...for just a few more
minutes though. I took it to Pep Boys and they said they think its a
problem with the 'Vent Door' under the dash, or something like that. I
called the dealer and they think it might be something else (no
description given). I want to get some ideas of what it might be
before I take it in to get it fixed and get a $2000 bill (slight
exaggeration there). Anyway...what do you guys think?

Thanks!
Steve

Many new HVAC systems regulate temperature inside the cab by moving a
blending door to choose between the heater core which is always on full, and
the A/C core which may or may not be on depending on your selection of
switches on the dash. When the A/C compressor is called for, the cooling
coil will tend to maintain a cold temperature, just like the heater coil
maintains one hot temperature, and you would then select a position for the
damper door to get a blend of the two temperatures which makes you all comfy
in the cab.

If the temperature output of your unit is swinging wildly, it must be that
the blending door is malfunctioning. It is usually operated by using engine
vacuum connected through a small hose to the switches or thermostat on your
dash, then to a small damper motor connected to the blender door. Something
in that series is not working properly .. A common problem is often that you
have a vacuum leak somewhere else around the engine compartment that is not
leaving the HVAC system enough vacuum to operate properly. Look for hoses
under the hood that have been pinched, or left off by some previous work ...
or that a rodent has chewed through etc. Listen around the engine
compartment for some constant hissing ... repair as needed.


"Steve" <steveindfw@yahoo.com> wrote in message
news:180ac350.0401281406.291a5210@posting.google.c om...

What vehicle uses a vacuum motor to control the blend air door? How would
you control that positionally? It would be less costly to use a stepper
motor to position the door. What type of climat control does it have
(automatic temp or manual)?

--
If at first you don't succeed, you're not cut out for skydiving

"nItpIk" <bubba@mindspring.com> wrote in message
news:ULpYb.340$f55.19558@news.uswest.net...

FYI - I found out that it IS the blend door and the blend door motor
that have gone bad. Hmmm. Well, Dodge (Chrysler) is setting me back
$800 to get those things installed...its crazy. Unfortunately they
have to completely remove the dash to get to those parts, so the labor
is what's jacking up the price so high. I looked at several good local
repair guys, just to see if I can get a better deal, and none of them
would even touch a job that complicated. Oh well.

"TBone" <t-bonenospam@nc.rr.com> wrote in message news:<4t3_b.26212$%d3.2381549@twister.southeast.rr .com>...

Have them recomend or authorize a dealership to do the work as well.

--
If at first you don't succeed, you're not cut out for skydiving


"Steve" <steveindfw@yahoo.com> wrote in message
news:180ac350.0403012127.236ba584@posting.google.c om...