2001 T&C Climate Control

Hello,

I have a 2001 town and country limited. Recently, the HVAC system has
become erratic. On cold mormings, it used to put DELAY on the climate
control, and count down till warm air was avail....

Now, it just blows air like crazy in the back right when you start it,
and it NEVER does the delay.

I have checked the coolant Temp Sensor with an OBDII tool, and
monitored it during warm up. It was completely normal. Ive also
"Recalibrated" the motor doors holding POWER and ReCirc.....

Im at a loss here. My next guess would be the Infrared sensors. Does
the climate control system get input from the rear sensor even if the
climate control is turned off?

THANKS!!!!

 

I believe you are on the right track, If your scanner can pull codes from
the climate control/BCM you may find a fault code.
The infrared detects surface temp of the drivers and passenger seat along
with the back seats and adjust the temperature. If the sensor is faulty it
will cause that problem.

Glenn Beasley
Chrysler Tech

 

Glenn,

Thanks so much for your helpful reply. I actually realized that I
screwed up with the quesiton I asked......

What I meant to ask is if the climate control uses input from the rear
sensor even if the rear climate control is turned off?

be replaced, right? (You cant replace just the sensor...?)

Thanks again for your help!!

-gerry

 

BTW---I have what is mostly a generic scan tool. So, it will not pull
codes from the BCM/Ac unit (Sadly....)

I would expect that I would need the chrysler scan tool to do this,
correct?

Do you see those infrared sensors go bad a lot?

-gerry

 

Are you sure the switch for the rear isn't set to manual control by the back
passengers. Sounds like it to me. Check the blower switch for the rear, Is
it on?

 

I wish it was that simple!! ......You can override manual control
anyway from the front. (Options are Off, Auto and Rear Control)

When you put it on Auto from the front, a lock icon appears on the rear
lcd, and control is disabled.

-gerry

 

I guess I still don't understand what you are saying, The dual infrared
sensor checks the front and rear surface temp. Yes they do go bad especially
if someone were so clean the lens with a vinyl dressing.. You don't have to
have a Chrysler scan tool just a scan tool that performs more options. I
would start with scanning the system before just putting parts on the
system.

Glenn Beasley
Chrysler Tech

 

Okay....thanks.

This van has two sensors....One in the front that takes care of both
front occupants, and one in the rear...

I was just asking if the climate control system still takes input from
the rear occupant sensor even if the climate control system for the
REAR is off. (And the front is on)

I ask this, because it seems as though the Rear Climate control is the
erratic one, as the fan for the back goes crazy upon starting the van.
Even if I shut the rear off, the front still doesnt act normally. I
find it unlikely that BOTH sensors would go bad, and hence why I ask
this question....

I really appreciate you help. Thats an interesting point regarding the
vinyl cleaner. I do use the armor all wipes, so its possible I nuked
the front sensor. But---it still wouldnt explain why the back climate
control (With its own sep. sensor) goes nuts. Ive never armor all'd
back there

Can the chrysler scan tool extract what temperature the Infrared Sensor
sees? I know with my 04 Acura TL, I can put the climate control in a
diag mode, and it will display a whole bunch of info about the climate
control without using a scan tool. (Including the in car temp, blend
door temp etc....) Similar on how you can hold the Trip button on the
T&C to get OBDII codes. (Really cool feature!!) Are there any special
modes to get this info out without a cabable scan tool??

Thanks again for your input. I highly value it!

-gerry

 

I had a similar problem with my 2001 T/C LTD and what had happened was
a short in the wiring from the outside air temperature sensor which
would give a faulty outside air temperature. ie. 5 degrees F would
show as 76 degrees F and this input is fed to the auto climate control
system which would try adjusting the cabin temp by bringing in outside
air without the time delay you usually get with cold temperature
starts. I ended up having to repair the wiring harness but the same
situation could happen with a faulty outside air temp sensor. The
control system does rely on the outside air temp to calculate the
opening of the HVAC unit blend doors as well as fan speed.

Johnny

 

Glenn

"The infrared detects surface temp of the drivers and passenger seat
along
with the back seats and adjust the temperature. If the sensor is faulty
it
will cause that problem. "

Interesting. Do you know where the sensor(s) are in the 2001 LHS?

Thanks
Bob AZ

 

The LH does not use the infrared sensor, it uses something called an
aspirator motor. It draws cabin air over the in car temp sensor. The air
flows across the resistor and of course the resistor changes resistance
depending on the temp sampled. This of course adjust the temp as needed.
That sensor is mounted behind the controller. If you ever suspect a problem
with this, pop out the control head and blow off the little fan behind it.
Those fans act as a magnet to dust.

Glenn Beasley
Chrysler Tech

 

Johnny,

I assume with your problem, your Outside Temp gauge read faulty also,
right? Ours is pretty dead on. Although once we were driving to go
skiing, and I noticed that the outside temp gauge would swing +/-8 or
so degrees in a very short distance on the highway. I was thinking
that with Averaging, maybe I wouldnt notice a bad sensor. But maybe it
was really swinging in temp driving in the mountains....

Thanks

-gerry

 

you need to get codes from the bcm the fcm and the hvac modules before
anything is done then use the codes to give you a direction to go
the rear hvac is controlled by the front and can be shut off from the
front which is the blower switch
spill any pop while it sat in the cupholder???

 

nax doesn't the lh have a single one in the center on the atc heads

 

Its not an infrared sensor on the LH

 

Actually my first symptons were the outside temp display would swing
up and down from 10 to 40 degrees of actual usually higher depending
on how much salty roadwater got into the harness during wet winter
driving. The sympton never appeared during warm weather months. But
as I said before it severely affected the auto climate control when
the outside temp display was reading faulty. So the ATC must really
rely on the outside temperature to regulate passenger compartment
temperature.

Johnny