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Error Code B1340 & B1344 Air Mix Door

1987 Views 8 Replies 3 Participants Last post by  DavidDor
I have both these error codes for Air Mix Doors. Can anyone help me to locate these? I would like to add that I already took off the underside of the dashboard driver side and center cover by the gas pedal. I can hear a grinding gearing sound, I am assuming that is coming from one of these Air Mix Doors. That sound is coming from up and behind the parking brake. Not sure how to get to it. FYI, I changed one of these doors out several years ago near the radio in the center of the dash board. Could that have gone bad already?

Thanks

Dave D.
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we ALWAYS ask for code DEFINITIONS - there are thousands of them -
no one has them all memorized - some might remember them wrong -

B1340 - Air Mix Door One Movement Fault -
this is the DRIVER side mix door actuator -
controls the air temp for the driver side -

B1344 - Heater Defrost/AC Door Movement Fault -
this is the MODE door actuator -
controls WHERE the air blows from -

without knowing the year - make - and model of the car -
no one can tell you what parts you need -
the best place to get them -
or how to replace them -
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1998 Cadillac STS V8
that's what we need -

left MIX door actuator
ACDELCO 15-72972 - $64 - with free shipping -
https://www.ebay.com/itm/GM-8901837...m2ac26e395d:g:LqwAAOSw8NNcSLjc&frcectupt=true

or $80 - with free shipping -
https://www.amazon.com/s?k=ACDELCO+15-72972&me=A2Q93MABOHRVLF&ref=nb_sb_noss

Mode door actuator -
ACDELCO 15-72631 - $58 - including shipping -
https://www.amazon.com/s?k=ACDELCO+15-72631&me=A1Q68YJNWKBEZO&ref=nb_sb_noss

or $53 - with free shipping -
https://www.ebay.com/itm/ACDelco-15...m43fcfdd79d:g:3pYAAOSwkNZUkO~Y&frcectupt=true

--------------------------

it is easier to replace the MODE door actuator when you remove the left MIX door actuator -

for a HowTo - start here -
https://sparkys-answers.com/2010/12/2002-cadillac-deville-b0248-b0249-no-ac.html
YES - this is for a Deville - the Seville is the same procedure -

we made a few mods/updates to the procedure - go here -
https://www.cadillacforums.com/foru...7-2002-dts-has-clicking-noise-instrument.html
pay particular attention to post #21 -

and here -
https://www.cadillacforums.com/foru...43-b0249-dash-noise-climate-control-part.html
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Not sure how this is going to help me. BUT lets start with the driver side door issue first. May I state again, I can clearly hear a gearing noise coming underneath the driver side dash NOT by the gas pedal\center consul but on the other side by the PARKING BRAKE. Is this "left MIX door actuator" that is mentioned by basscatt above? If so, how do you get to it. Remove the Parking Brake assembly?

Also, let me mention two things. 1:) the HVAC system does work. Heat and AC work properly. Vents do change but I will try again. I live in Phoenix, never any need for heat. AC works fine. 2:) my battery keeps going dead. I had AutoZone check out the system and it is all okay. Now, I see reading the suggested links, that this Mix Door Actuator can lead to power loss. I can say for certain that when I turn the car off, I continue to hear the gearing sounds coming from under the dash board. Could this be Mix Door issue lead to draining the battery?
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you have two diagnostic trouble codes -

one for a faulty left MIX door actuator - B1340 -

and the other for a faulty MODE door actuator - B1344 -

these actuators are located up in the HVAC stack - to the left of the console -
I supplied the HowTo we have used numerous times to replace these actuators -

are these the source of your noise?
I don't know - sound travels - but they are no where near the parking brake pedal -

my battery keeps going dead.
I had AutoZone check out the system and it is all okay.

take it somewhere else and have it LOAD TESTED -

there is a simple way to distinguish between a bad battery and a parasitic draw -
disconnect BOTH battery cables -
fully charge the battery and let it sit for 24 hours -

re-test the battery -

if the battery is dead -
it MUST be an internal short - a defective battery -

if the battery is still fully charged -
you have a parasitic draw -
SOMETHING isn't shutting down when it is supposed to -

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Now, I see reading the suggested links,
that this Mix Door Actuator can lead to power loss.

I can't imagine how a faulty mix door or mode door actuator could possible drain a battery -
once the ignition key is turned off -
the entire climate control system is turned off -

I can say for certain that when I turn the car off,
I continue to hear the gearing sounds coming from under the dash board.

well - I can't imagine what you are hearing -
the easiest way to discover the source would be to climb under the dash and pinpoint the noise -

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the only other thing that comes to mind is the cabin temperature sensor -

it is located behind the 1 inch square grill on the dash - left side of the steering column -
there is a little fan that draws cabin air across a thermistor -
the fan bearing could be dried out and making noise -
HOWEVER -
this is also turned off when the ignition is turned off -

----------------------

OH - one other thought - AFTER-BLOW -
but I'm not even sure it was available in the 1998 -

AFTER-BLOW is/was a special setting that the dealer could set up
that would keep the main fan blowing for up to 10 minutes after the ignition was turned off -
this was done to completely dry off the evaporator core
to prevent mold/mildew from growing on the wet core - thus causing a bad smell -

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