Centre vent temperature sender -G191
A - Connector of temperature sender -G191
B -Centre vent temperature sender -G191
C - Sealing ring
D - Mount,
centre vent temperature sender -G191
The air conditioner is regulated within an
overall temperature range between 18°C and 28°C. However, the possibilities of
individual climate settings for each selectable position must be set against
the fact that the climate zones are not physically separated from each other.
In the selected automatic function the air
conditioner uses the sensors to determine how much the air for the climate zone
concerned needs to be heated or cooled in order to deliver the selected
The Climatronic control unit decides based
on the request for example that regulated warm or cooled air should be routed
into the driver or front passenger climate zone as appropriate to provide
The climate control is fully automatic, with separate
air temperature control for the left and right sides of the passenger
The centre vent temperature sender -G191
is located in the air duct to the right side dash panel vent.
The air flowing out of the heater/air
conditioner unit into the passenger compartment is recorded with a
temperature-dependent resistance and so is available as an influencing variable
in the temperature monitoring and control function of the Climatronic control
unit -J255. The temperature sender -G191 is
designed as an NTC sensor. The
resistance is evaluated as a signal from the control unit and regulates the air
distribution and delivery rate of the blower.
J As the temperature falls
the electrical resistance increases.
J If the fault: "short to
earth" is detected by the Climatronic control unit -J255, the value 150°C
is entered in display zone 3 of measured value block 017.
J If the fault: "open
circuit/short to positive" is detected by the Climatronic control unit
-J255, the value -70°C is entered in display zone 3 of measured value block 017.
J If the centre vent temperature
sender -G191 fails, operation is maintained.
J Experience shows that
temperature senders are the most frequent cause of temperature control faults. They do not usually fail immediately,
but deliver false values to the control unit based on an additional wire
resistance as a result of damage or corrosion in the connector contacts. Thus a comparison with the
values of senders -G150, -G151 and -G191 in the relevant display zones is recommended
for optimum diagnosis.
A Air conditioner; Rep.Gr. 87;
Removing and installing left vent temperature sender -G191
A Current flow diagram; ELSA
Measured value block 017
Display zone 1
Readout of left vent temperature sender -G150 in °C.
Display zone 2
Readout of right vent temperature sender -G151 in °C.
Display zone 3
Readout of centre vent temperature sender -G191 in °C.
Display zone 4
Currently not used