Checking operation of electronics in heater control unit J65 and of fresh air and air recirculation flap control motor V154 — AUDI

Checking operation of electronics in
heater control unit
J65
and of
fresh air and air recirculation flap control motor
V154
Note
As of Model Year 2010 a start/stop system will be available as an optional extra for this vehicle in conjunction with certain engines. On vehicles with a heater only (no
“air conditioner”
optional extra) the
heater control unit
J65
has no effect on the start/stop function.
Remove the glove compartment
General body repairs, interior
Rep. gr.
68
.
Switch on ignition.
Move the rotary air distribution control
B
to the
“air distribution to dash panel vents”
position.
Fresh-air/air recirculation button
F
not pressed (fresh air mode, lamp in button does not light)
To check the voltage, connect a voltage tester to the connector
A
between contacts
“9”
and
“10”
, e.g.
voltage tester
V.A.G 1527 B
B
(to
fresh air and air recirculation flap control motor
V154
).
Press the fresh-air/air recirculation button (lamp in button lights).
“Earth”
is constantly or briefly applied to contact
“9”
(depending on the control unit version) and
“Positive”
is constantly or briefly applied to contact
“10”
.
The
fresh air and air recirculation flap control motor
V154
and thus the fresh air/air recirculation flap are moved to the
“air recirculation mode”
position (the air recirculation intake opening
C
is opened).
Press the fresh-air/air recirculation button
F
(air recirculation mode, lamp in button goes out).
Note
Pressing the fresh air/air recirculation button
F
causes the
heater control unit
J65
to alter the power supply to the
fresh air and air recirculation flap control motor
V154
(positive and negative are interchanged).
Depending on the version of the
heater control unit
J65
, positive is applied either constantly or only for a certain period after pressing the fresh-air/air recirculation button. Once this period has elapsed, the control motor is only actuated with a specific duty cycle in the case of control units to which voltage is only applied for a certain period (the lamp in the
voltage tester
V.A.G 1527 B
only flashes briefly).
“Earth”
is constantly or briefly applied to contact
“10”
and
“Positive”
is constantly or briefly applied to contact
“9”
.
The
fresh air and air recirculation flap control motor
V154
and thus the fresh air/air recirculation flap are moved to the
“fresh air mode”
position (the air recirculation intake opening
C
is closed).
Note
The control motor connections are interchanged on right-hand drive vehicles.
Current flow diagrams, Electrical fault finding and Fitting locations
If no fault is found in this test:
Check the freedom of movement of the fresh-air/air recirculation flap.
Replace the
fresh air and air recirculation flap control motor
V154
Chapter
.
If the function is not OK:
Check for open circuit or short circuit in the wiring between the
heater control unit
J65
and the
fresh air and air recirculation flap control motor
V154
Current flow diagrams, Electrical fault finding and Fitting locations
.
Check the power supply and earth connection to the
heater control unit
J65
Current flow diagrams, Electrical fault finding and Fitting locations
.
Replace the
heater control unit
J65
Chapter
.