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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
PROCEDURE
STEP #1:
➢ Confirm NOK Condition (loose linkage to flap)- Minor Disassembly!
A) Remove the RIGHT, side under-dash panel and footwell duct.
*See Reference Picture: “D- Under-dash & Footwell Duct”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: D- Under-dash & Footwell Duct

Under-Dash Panel
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Footwell Duct
5

G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #1 (Continued):
➢ Confirm NOK Condition (loose linkage to flap)- Minor Disassembly!
B) Locate and wiggle the linkage connecting arm between the cold and warm mixing flaps and look for
excessive looseness at the lower end of the linkage connecting arm and directly at the warm mixing flap
pin/linkage (connection to the warm mixing flap). A boroscope could also be helpful.
*See Reference Picture: “E- VIEW after under-dash and footwell duct removed”
See video: BV640525 Confirm warm mix linkage and flap is loose.MOV

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: E- VIEW after under-dash and footwell duct removed
MOTOR #11-M022
Controls RIGHT,
Footwell flap #6B

Linkage connecting
arm Right side cold
(#4B) & warm (#5B)
linkages & flaps
(controlled by MOTOR
#9-M83 ).
(YELLOW PART)
PIN/LINKAGE that
connects to warm
air flap #5B.

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #1 (Continued):
➢ Confirm NOK Condition (loose linkage to flap)- Minor Disassembly!
C) In some cases, you may find it easier to remove motor #11/M022 for the ”loose” inspection/confirmation.
Note: This not the controlling motor for the mixing flaps. It is the controlling motor for the RIGHT, side vent air
flap #8B. However, this motor is in the way & partially covering up the warm mixing linkage connection to flap.
Removal of this motor is ok (if needed). If the warm mixing linkage to flap is loose, this motor will have to be
removed later anyway to be able to fix the loose condition.
*See Reference Picture: “F A/B- Remove MOTOR #11-M022”
*See Reference Picture: “G-RH Temperature Mixing Complete Kinematics”
*Reference Master Info: “G45 HVAC: Air Vent Flaps/Kinematic & Stepper Motor Master Info”
See video BV640625 Confirm warm mix linkage and flap is loose motor removed.MOV

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: F A- Remove MOTOR #11-M022

#11- M022
Front Side Vent Air Distribution
RIGHT

RIGHT Front Side Vent Flap #8B
(controlled by MOTOR #11-M022)

(LHD: Right Side VIEW)
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: F B- Remove MOTOR #11-M022
MOTOR #11-M022
MOTOR #11-M022 REMOVED!
REMOVED!
Pin/Linkage for RIGHT, side
Pin/Linkage for RIGHT,vent
sideair flap #8B.
vent air flap #8B.
Linkage connecting arm
Right side cold (#4B) &
warm (#5B) pins/linkages
&Linkage
flaps (controlled
by
bar connecting
MOTOR
). &
Right side#9-M83
cold (#4B)
warm (#5B) pins/linkages
& flaps (controlled by
MOTOR #9-M83 ).
(YELLOW PART)
PIN/LINKAGE that
connects to warm
air flap #5B.
PIN/LINKAGE that
connects to warm
air flap #5B.
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: G- RH Temperature Mixing Complete Kinematics

Linkage connecting arm
Right side cold (#4B) &
warm (#5B) pins/linkages
& flaps (controlled by
MOTOR #9-M83 ).

(YELLOW PART- All one
piece!) PIN/LINKAGE that
connects to warm air flap
#5B.

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
AFTER STEP #1.... STOP!
➢ STOP & Evaluate!
•

If the linkage/flap is NOT loose (per the videos already mentioned) stop this checklist and review
other potential causes (i.e. NOK stepper motor, wiring, other).

•

If the linkage/flap IS confirmed to be loose (per the video already mentioned) proceed to the next
steps (see steps #2 - #10 below)...

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #2 (ONLY if Loose Linkage Confirmed in STEP #1!):
➢ Carefully remove all necessary additional parts!
Remove Upper Instrument Panel (IP) skin (& any other components necessary to take the IP skin off).
Please refer to AIR Premium Repair Instructions
51 45 051 | REP-REP-P-5145051-G45 - V.2
Overview here:

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #3, #4, & #5:
➢ Create access for proper counterforce & repair!
3) Via OBD/ISTA, Fully OPEN the front RIGHT, center vent air flap #7B (controlled by stepper motor #12M22) to 100%.
NOTE: Completely opening this flap allows access for a screwdriver (or similar) to access and apply
counterforce to the RIGHT, warm mixing flap (#5B) during pin/linkage installation.
*See Reference Picture: “H- OPEN Right Side Center Air Vent Flap #7B”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: H- OPEN Right Side Center Air Vent Flap #7B

OPEN Right Side
Center Air Vent Flap
#7B. Controlled by
Motor #12-M22

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M 22
(#12)

7B

15

G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #3, #4, & #5 (Continued):
➢ Create access for proper counterforce & repair!
4) Via OBD/ISTA, Fully CLOSE the the front RIGHT, mixing flaps (connected) #5B: WARM & #4B: COLD
(controlled by stepper motor #9-M83) to 0%.
NOTE: Completely closing this flap makes it easier to apply counterforce to this flap (#5B) during pin/linkage
installation.
NOTE: Flaps are NOT visible from outside of HVAC Box!
*See Reference Picture: “I- CLOSE Right Warm Mixing Flap #5B”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: I- CLOSE Right Warm Mixing Flap #5B
#9- M83
Front Temperature Mixing RIGHT

CLOSE Right Side WARM
Mixing Flap #5B
(FLAP NOT VISIBLE).
Controlled by Motor #9- M93

(LHD: Right Side VIEW)

Housing transparent to
show closed flap #5B

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #3, #4, & #5 (Continued):
➢ Create access for proper counterforce & repair!
5A) If not already completed in step #1C (above), remove stepper motor #11-M022 (screws and motor) in
order to access loose RIGHT, warm mixing flap pin/linkage & for for better visual access.
NOTE: This is the controlling motor for the RIGHT, side vent air flap #8B. This must be completed to provide
access to grab warm mixing linkage to press into the flap #5B (later).
*See Reference Pictures: “FA & FB- Remove MOTOR #11-M022”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: F A- Remove MOTOR #11-M022

#11- M022
Front Side Vent Air Distribution
RIGHT

RIGHT Front Side Vent Flap #8B
(controlled by MOTOR #11-M022)

(LHD: Right Side VIEW)
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: F B- Remove MOTOR #11-M022
MOTOR #11-M022 REMOVED!
MOTOR #11-M022 REMOVED!
Pin/Linkage for RIGHT,Pin/Linkage
side
for RIGHT, side
vent air flap #8B.
vent air flap #8B.
Linkage connecting arm
Right side cold (#4B) &
warm (#5B) pins/linkages
& flaps bar
(controlled
by
Linkage
connecting
MOTOR
). &
Right
side#9-M83
cold (#4B)
warm (#5B) pins/linkages
& flaps (controlled by
MOTOR #9-M83 ).
(YELLOW PART)
PIN/LINKAGE that
connects to warm
air flap #5B.
PIN/LINKAGE that
connects to warm
air flap #5B.
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #3, #4, & #5 (Continued):
➢ Create access for proper counterforce & repair!
5B) Via OBD/ISTA, also OPEN the Front RIGHT, Footwell Flap #6B (controlled by MOTOR #4-M7).
NOTE: This will allow for visual checks (later) with boroscope or mirror.
*See Reference Pictures: “J- OPEN Front RIGHT, Footwell Flap #6B”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: J- OPEN Front RIGHT, Footwell Flap #6B
6B

M7
#(4)

#4- M7 Front Footwell
Air Distribution RIGHT

Front RIGHT, Footwell Flap #6B
(controlled by MOTOR #4-M7)

(LHD: Right Side VIEW)

Flap #6B
OPEN View

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #6:
➢ Provide significant outboard counterforce to the warm mixing flap
#5B!
NOTE: A flathead screwdriver (or similar) is needed for this step. A flashlight could also be helpful.

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #6 (Continued):
➢ Provide significant outboard counterforce to the warm mixing flap
#5B!
Pass the shaft of the screwdriver through the OPEN RIGHT, center vent air flap (#7B),
through the small hole (in housing), and all the way down to the CLOSED warm mixing flap #5B. Align the
flat edge of screwdriver to the solid plastic ribs on the CLOSED warm mixing flap #5B.
After screwdriver is inserted and properly aligned to the warm mixing flap #5B (in one of the designated
locations) wedge/press the flathead to the flap and pry it hard outboard.
NOTE: The goal is to provide some stiff counterforce to the warm mixing flap #5B (to remove side-to-side
movement of this flap and force it outboard) at the same time you push hard and fully engage the pin/linkage
to flap (please see next steps for more detail).
NOTE: The warm mixing flap #5B could inadvertently move to the open position since the flap and linkage are
loose at this point. If this happens, push the pin/linkage in as far as you can and then rotate flap to completely
close it again. This will make providing the necessary screwdriver counterforce easier.
*See Reference Picture: “L- Position screwdriver through center vent, hole, and align to flap #5B”
*See Reference Picture: “M- Wedge/Pry Locations on Warm Mixing Flap #5B”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: L- Position screwdriver through center vent, hole, and
align to flap #5B

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: M- Wedge/Pry Locations on Warm Mixing Flap #5B

X

Main positions to locate and wedge/pry the
flathead screwdriver for needed outboard
counterforce on flap!

X
X
X
X

Increasing ZOOM to show details!
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #7:
➢ FULLY ENGAGE pin/linkage to the warm mixing flap #5B!
AT THE SAME TIME AS YOU ARE CONTINUING STEP #6...
Grab the warm mixing linkage and PUSH HARD INBOARD to FULLY ENGAGE the loose pin/linkage into the
warm mixing flap #5B .
Push BOTH the warm mixing pin/linkage (with your hand/fingers) AND the warm mixing flap #5B (with a
screwdriver), towards/into each other at the same time to secure FULL Engagement.
PUSH HARD until the pin/linkage mushroom head is fully secured completely over the ramp!
Step 7 from OUTSIDE the HVAC box see video:
BV640725 Flap held secure during linkage install.MOV
Step 7 from INSIDE the HVAC box see video:
BV640825 Flap held secure during linkage install.MOV
If you FAIL to secure/provide significant counterforce to the flap, at the same time you engage the
pin/linkage, then it is possible for it to NOT fully engage even if it may feel like it is!

For a view of loose linkage OUTSIDE the HVAC box see video:
BV640325 Linkage NOT fully engaged even with hard push yet appears ok.MOV
For a view of loose linkage INSIDE the HVAC box see video:
BV640425 Linkage NOT fully engaged even with hard push yet appears ok.MOV
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #8:
➢ Confirm FULL Engagement (Visually & by Manually Pulling)!
8A) Review that the pin/linkage mushroom head is FULLY over the ramp on the flap
(visually via articulating boroscope &/or mirror through the RIGHT, side footwell flap #6B).
*See Reference Pictures: “A, B, & C- Fully Engaged vs NOT Fully Engaged”

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: A- Fully Engaged vs NOT Fully Engaged

CAD
Section
Cut

NOK!
Main References:
--- FULLY Engaged ----- NOT FULLY Engaged --

Real Part

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: B- Fully Engaged vs NOT Fully Engaged

NOK!

OK

NOK!

FULLY ENGAGED

Barely short of FULL engagement!

Pin/Linkage Mushroom Head
Completely Over Ramp on Flap!

Pin/Linkage Mushroom Head NOT
Completely Over Ramp on Flap!

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
Reference Picture: C- Fully Engaged vs NOT Fully Engaged

NOK!

NOK!
FULLY ENGAGED
Short of FULL engagement!

Pin/Linkage Mushroom Head
Completely Over Ramp on Flap!

Pin/Linkage Mushroom Head NOT
Completely Over Ramp on Flap!

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS
STEP #8 (Continued):
➢ Confirm FULL Engagement (Visually & by Manually Pulling)!
8B) Then, manually pull on the fully seated pin/linkage (detailed in step #1B/#1C above).

You should be able to pull fairly hard if the connection is completely engaged and secure.
If not fully engaged, you will be able pull it out again with only low to medium force (vs high force).
See low force video: BV640925 Linkage NOT fully engaged appears ok Actually NOK.MOV
See low force video: BV641025 Linkage NOT fully engaged appears ok Actually NOK.MOV
See High force video: BV641125 Hard to pull out once fully engaged OK.MOV
Note: Partial engagement already has some tension which may give the feeling of FULL engagement even if
NOT FULLY engaged! When, not completely engaged, the function could even be ok for several
cycles/rotations before it will eventually fail again. This is why you must be certain!
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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS

STEP #9:
➢ Test Cycle Flap Function 30 times & Re-check Engagement!
A) Reinstall motor #11-M022 (previously removed for access).
B) Run the normal stepper motor calibration.
C) Test cycle (via ISTA) motor #9-M83 (full cycle: 0% to 100%).
This should be repeated 30 times since it may take several cycles to fail again!
NOTE: The failure only occurs if pin/linkage is not properly/fully engaged to the flap!
D) Reconfirm once again that linkage is still fully engaged.
This should be done visually (with boroscope or mirror) and manually (wiggle and pull pin/linkage by hand).
Both methods are detailed in steps #8A/8B and #1B/1C above!
If not fully engaged, you will be able pull it out again with only low to medium force (vs high force).
See low force video: BV640925 Linkage NOT fully engaged appears ok Actually NOK.MOV
See low force video: BV641025 Linkage NOT fully engaged appears ok Actually NOK.MOV
See High force video: BV641125 Hard to pull out once fully engaged OK.MOV

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G45 HVAC: UPDATED MIXING FLAP 5B INSTRUCTIONS

STEP #10:
➢ Carefully reinstall all parts!
If all checks are OK, reinstall IP cover and all other components.

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