Temperature Sensor/Overheating Sensor; Removing Temperature Sensor/Overheating Sensor; Installing Temperature Sensor/Overheating Sensor; Checking Sensors - Webasto thermo top evo Workshop Manual

Thermo Top Evo
9.6 Temperature sensor/
9.6.1 Removing temperature sensor/
overheating sensor
For information on removing heater cover, see
Section 9.1.1. Pull connectors of sensors out of control unit.
When doing so, make sure connector lock is released.
Loosen screw (W3, see Fig. 204), remove retaining spring
(W4) and pull sensors (W5 and W6) out of heat exchanger
(W1).
The sealing O-ring of the sensor can stick to the housing
after some operating time, preventing its removal. Once
sensors have been remove, they cannot be reused and must
be replaced with new ones.
9.6.2 Installing temperature sensor/
overheating sensor
The gaskets of the sensors must be moistened with water or
antifreeze prior to installation in the heat exchanger.
1.
Fig. 918 Moistening gaskets
2.
W5
Fig. 919 Position retaining spring
while watching cable routing and position of
sensors W5 and W6
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verheating sensor
O
NOTE
NOTE
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3.
Fig. 920 Mounting screw
4.

Fig. 921

Tightening screw

9.6.3 Checking sensors

When checking the cold resistance, a distinction must be
made between the variants sensors W5 and W6 (see Section
9.6.2 and Fig. 204). To do this, the contacts of connector X3
of the sensors are connected to a multimeter and the resist-
ance is measured.
Sensors Contacts on
connector X3
W5 2 and 4
W6 1 and 3
W6

Fig. 922 Sensor resistance values

In addition, the short-circuit to earth to the metal housing,
wire crimpings and deformations of the plastic cap of the
sensors must also be checked.
The sensors need not be removed for checking.
9 Repair
4 ± 0.4 Nm
Cold resistance at
20 ± 6 °C [ohms]
min. max.
2,296 5,047
30 250
NOTE
907