Bentley R Type - Electrical Fault Location

98
Tnr
'R'
Typr
Brurr,By.
to
a booster
motor
mounted
in front
of the
dashboard. Then,
through
suitable
ducting,
to
vents in the
capping
rail.
The normal
forward
motion
of the
car is
usually
sufficient to
ensure adequate
de-misting,
and
it
is
only under
severe
conditions,
or
if de-frosting
is
required,
that
the
booster
motor need
be
used.
The
vents are fitted
with
metal
covers, and these
should normally
remain
open,
but
they
may
be closed
if it is
found
that
warmed air
is
being
drawn into
the
car at
unseasonable
times.
To operate
for normal
de-misting,
ensure that
the
vent
covers
are
open
by
gently
pulling
same rearwards.
For
severe
conditions
or
de-frosting,
switch
on booster
motor (18,
Fig. 1).
The
rear
window
is
of the
electrically
heated
type, and contains
a
series
of wires
moulded
into
the
glass.
A
switch on the facia
board
marked
"R.'W."
controls
this feature
as required.
Electrical
Fault
Location.
In
case of faulty
operation,
proceed
to
investigate
as
follows:-
r.
Failure
of any
part
of
the
system separately,
may
be
due to
a
blown
fuse
in
the fuse
box
(Fig.
42\.
z.
Failure
or
incorrect
operation
of the
system, may be due to the
fusing of
the main
fuse
(Fig.
42),
due to
an
earth.
If the
dynamo
does not
charge:-
r.
Check
correctness
of ammeter
by switching on headlamps;
this
should
show
a
"discharge"
reading.
NOTE:-See
that
the
main switch
is
in
the
"OFF'f
position,
before
making
any
change
to the wiring connections.
z.
Ascertain
whether
the
dynamo
or
regulator
unit
is
at
fault by
connecting
together
the regulator
teininals F and D; this
wiil
short
circuit
the regulator.
Start
engine gently
and
increase
speed slowly,
engine
speed should
not exceed a
fast idle.
Observe
ammeter; if
dynamo is in
order the ammeter
will show a
"charge"
reading
and
the
defect will
be in
the regulator
unit.
3.
To
test dynamo,
disconnect
the
wiring
from
both
main
terminals
and
conneit
these terminals
together.
Connect
a lamp
between
one
terminal
and
eartb,
and
gently
speed up
engine as
before.
If
the dynamo
is in
order the
lamp will lighl.
4.
iDynamo
brushes
may
be
sticking, due
probably
to oiliness.
Clean brushes
and
holders
with
rag
moistened
in
petrol.
5.
Cut-out
contacts
may
be burnt out or
sticking.
If dynamo
output
is
low,
this
may
be due to the
battery being fully
charged,
but
if
low
with
lights
on,
i.e.,
ammeter
indicates an abnormal
discharge,
the regulator
may
be
sticking
in
such
a
manner
as
pennan-
ently
t_o i-nser!
the field
resistance.
Low
output may also
be
caused
by
a slack driving
belt,