Shibaura ST330, Workshop Manual

Page: 223 / 250

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26) BRAKE light RELAY
(No.385230250)
T h e brake light relay is installed on the
botto m of steering co lu mn in the dashbo ard,
and it is co nnected with wh ite connecto r of
main wire h arness.
The relay is automatically complete ( clo se) a
circuit.
The brake tight is a single-pole, single-throw
switch (SPST) th at contains three circu its.
One circu it is the control circuit, which
controls the relay's coil. The other two are
function circuits. The brak e light relay
switch es from on e function circu it to another
when the coil is energ ized. One function
circuit is alway s clo sed, wh ich d epends on if
th e relay 's coil is en ergized . The brake light
relay does not utilize an in ternal diode. The
master brake switch when closed , will
energize the b rake light relay co il, which
completes b rake lamp circu it. This allows
th e brak e lamps illu minate.
When the coil is not energized , the relay
completes the circuit for brake lamps.
If the operato r dep resses the master b rake
pedal the relay 's co il will energize, which
also close b rake lamps circu it.
Brake lig ht Relay Test
1. D i sconnect th e con necto r and remov e
the brake relay from th e tractor.
2. U sing an oh mmet er, conn ect test p robes
to terminals "C" and "D" on the relay.
Observe the ohmmeter r eading. Repeat
for terminals "D" and "E".
3. Th ere sh ould be high resistance betw een
terminals "C" and "D" and terminals
"D" and "E", ind icating no con tinuity
and that the relay is functioning
properly when non-energized. If there is
continu ity, the relay is d efective and
need s replaced .
581Y
582Y
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