Left vent temperature sender -G150
A - Connector of temperature sensor
B - Left vent temperature
C - Sealing ring
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 temperature.
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 ventilation.
The climate control is fully
automatic, with separate air temperature control for the left and right sides
of the passenger compartment.
The left vent
temperature sender -G150 is located on the left in the air conditioner unit.
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 -G150 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 The value of
the out-flow temperature is determined as a reference signal to the dash panel
temperature sensor -G56 on the right and left sides.
J As the
temperature falls the electrical resistance increases.
J The sender is
self-diagnosis compatible. A fault detected in the
sender is only registered by the Climatronic control unit -J255 if the coolant
temperature is detected as above 50°C.
J If the fault:
"short to earth" is detected by the Climatronic control unit -J255,
the value 150°C is entered in display zone 1 of measured
value block 17.
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 1 of measured
value block 17.
J If the left
vent temperature sender -G150 fails, the value of the intact vent temperature
sender -G151 is adopted. Operation is maintained.
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 of the values of all senders
(-G150, -G151 and G191) in the relevant display zones is recommended for
conditioner; Rep.Gr. 87; Removing and installing left vent temperature sender
A Current flow
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