5
Electrical installation
ELECTRICAL INSTALLATION
2-103
25. VOITH RETARDER
OPERATION
The electronic unit of the Voith retarder (D870)
is fed behind the contact through fuse E029.
If the ABS is active, wire 4619 is switched to
earth by relay G239. As a result, the Voith
retarder is deactivated.
The Voith retarder switch (C799) is fed through
wire 4710 and is equipped with 4 outputs
(positions 1 - 4) which are connected to the
Voith retarder unit. These are the 4 brake
positions.
This is how the electronic unit controls the Voith
retarder valve (B298).
If the coolant temperature is too high (measured
by the coolant temperature sensor (F544)), the
retarder control reduces the retarder pressure
by reducing the current through the proportional
magnetic valve.
A warning lamp on the instrument panel DIP-3
(D852) indicates whether or not the retarder is
active. A signal is also supplied to the CTE-2
unit (D550) through wire 3420 to disengage the
cruise control when using the retarder.
There is a connection on the CTE-2 unit to
supply the speed signal through wire 3502. This
wire is also connected to the electronic unit of
the Voith retarder (D870).
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