THDC / THDCP - 954 / 955 / 974 (Rev. 06/03)
THDC / THDCP - 954 / 955 / 974 (Rev. 06/03)
6-14
6-14
ifold valv
ifold valve.
e. The brake coolant pr
The brake coolant pressure sw
essure switch
itch
is a normally closed switch that will open at
is a normally closed switch that will open at
10 psi.
10 psi. The purpose of this s
The purpose of this switc
witch is to moni-
h is to moni-
tor for a low pressure problem in the brake
tor for a low pressure problem in the brake
cooling ci
cooling circuit.
rcuit. When the pres
When the pressure drops
sure drops
below 10 psi, the switch will then close com-
below 10 psi, the switch will then close com-
pleting the electrical circuit to the brake fault
pleting the electrical circuit to the brake fault
light (D
light (DS8).
S8). It must now be deter
It must now be determined if the
mined if the
switch (S23) is defective or if a low pressure
switch (S23) is defective or if a low pressure
problem exists in the brake cooling circuit.
problem exists in the brake cooling circuit.
There is a pressure test coupling (pressure
There is a pressure test coupling (pressure
check) located on the brake cooling manifold
check) located on the brake cooling manifold
at port A.
at port A. Plug a press
Plug a pressure gauge int
ure gauge into the test
o the test
port and with the engine running, observe the
port and with the engine running, observe the
gauge reading.
gauge reading. The max
The maximum
imum pressure
pressure
observed should be no more than 600 psi (the
observed should be no more than 600 psi (the
pressure will be between 0 and 600 psi).
pressure will be between 0 and 600 psi).
Remember it takes 10 psi to open the switch.
Remember it takes 10 psi to open the switch.
If the pressure indicated is above 10 psi, the
If the pressure indicated is above 10 psi, the
brake coolant pressure switch (S23) is defec-
brake coolant pressure switch (S23) is defec-
tive and must be replaced.
tive and must be replaced.
If all three of the switches, described above, have
If all three of the switches, described above, have
been prove
been proven to
n to be good
be good and the brake fault ligh
and the brake fault light is
t is
still illuminated, there is a short on the signal wire
still illuminated, there is a short on the signal wire
#32.
#32. Isolate a
Isolate and remove
nd remove the short
the short..
Front Wiper Circuit
Front Wiper Circuit
(Illustration 6-16)
(Illustration 6-16)
..
The front
The front
wiper circuit is comprised of a circuit breaker
wiper circuit is comprised of a circuit breaker
(CB4), wi
(CB4), wiper switc
per switch (S7) and wiper motor (B1)
h (S7) and wiper motor (B1).
. 12
12
VDC power is supplied from circuit breaker (CB4)
VDC power is supplied from circuit breaker (CB4)
to the B (Battery) posts of the wiper switch (S7).
to the B (Battery) posts of the wiper switch (S7).
There are 6 posts on the back of the wiper switch
There are 6 posts on the back of the wiper switch
(S7).
(S7). The P (Park) pos
The P (Park) post of the wiper sw
t of the wiper switch is
itch is
used for parki
used for parking the wiper motor (
ng the wiper motor (B1).
B1). When the
When the
wiper switch is turned off, 12 VDC will be present
wiper switch is turned off, 12 VDC will be present
at the P
at the P post
post.
. When the wip
When the wiper swi
er switch is turn
tch is turned on,
ed on,
12 VDC will be present at the L (Low) or H (High)
12 VDC will be present at the L (Low) or H (High)
post of the wiper switch (depending on desired
post of the wiper switch (depending on desired
speed
speed).
). 12 VDC wil
12 VDC will be present at the W (Wa
l be present at the W (Wash-
sh-
er) post of the wiper switch (S7) when the wiper
er) post of the wiper switch (S7) when the wiper
switc
switch is depressed.
h is depressed. Five wi
Five wires are used on the
res are used on the
wiper mot
wiper motor (B1).
or (B1). The black w
The black wire of the wiper
ire of the wiper
moto
motor is used for gr
r is used for ground.
ound. The blue wi
The blue wire of the
re of the
wip
wiper motor (B
er motor (B1) is is used for high speed.
1) is is used for high speed. The
The
yellow wire of the wiper motor (B1) has a constant
yellow wire of the wiper motor (B1) has a constant
12 VDC supply to it at all times while the key is at
12 VDC supply to it at all times while the key is at
the accessor
the accessory positi
y position.
on. The red wire of the w
The red wire of the wiper
iper
motor (B1) i
motor (B1) is used for low s
s used for low speed.
peed. In this applic
In this applica-
a-
tion, 12 VDC will be applied to the red wire when
tion, 12 VDC will be applied to the red wire when
the wiper sw
the wiper switch (S7) i
itch (S7) is in the Low positi
s in the Low position.
on. The
The
green wire of the wiper motor (B1) is used to drive
green wire of the wiper motor (B1) is used to drive
the wiper motor to the Park position when the wip-
the wiper motor to the Park position when the wip-
er swit
er switch (S7) is tur
ch (S7) is turned off.
ned off. There wil
There will be 12 VDC
l be 12 VDC
present on the green wire when the wiper switch
present on the green wire when the wiper switch
(S7) is in the Park position.
(S7) is in the Park position.
Top and Rear Wiper Circuits
Top and Rear Wiper Circuits
(Illustration 6-16)
(Illustration 6-16)
..
The top and rear wiper circuits are comprised of a
The top and rear wiper circuits are comprised of a
circuit breakers (CB3 and CB24), wiper switches
circuit breakers (CB3 and CB24), wiper switches
(S8 and S9) and wipe
(S8 and S9) and wiper motor
r motors (B8 and B9).
s (B8 and B9). 12
12
VDC power is supplied from circuit breaker (CB3)
VDC power is supplied from circuit breaker (CB3)
to the B (Battery) post of the wiper switch (S8)
to the B (Battery) post of the wiper switch (S8)
while 12 VDC power is supplied from circuit break-
while 12 VDC power is supplied from circuit break-
er (CB24) to the B (Battery) post of the wiper
er (CB24) to the B (Battery) post of the wiper
swi
switch (S9
tch (S9).
). Ther
There are 5
e are 5 post
posts on the back of the
s on the back of the
wiper sw
wiper switches (
itches (S8 and S9).
S8 and S9). The P (Park) pos
The P (Park) post of
t of
the wiper switches are used for parking the wiper
the wiper switches are used for parking the wiper
motor (B9 and B8).
motor (B9 and B8). When the wiper s
When the wiper switches
witches are
are
turned off, 12 VDC will be present at the P post.
turned off, 12 VDC will be present at the P post.
When the wiper switches are turned on, 12 VDC
When the wiper switches are turned on, 12 VDC
will be present at the L (Low) post or H (High) post
will be present at the L (Low) post or H (High) post
of the wiper switches, contingent on the speed
of the wiper switches, contingent on the speed
selected.
selected. 12 VDC wil
12 VDC will be present at the W (W
l be present at the W (Wash-
ash-
er) post of the wiper switches (S8 or S9) when the
er) post of the wiper switches (S8 or S9) when the
wiper swi
wiper switch is depressed.
tch is depressed. With the wiper sw
With the wiper switch
itch
(S8 or S9) turned off, 12 VDC is applied at the P
(S8 or S9) turned off, 12 VDC is applied at the P
terminal of the wiper motor (B9 or B8) to drive the
terminal of the wiper motor (B9 or B8) to drive the
wiper mot
wiper motor to the Park posit
or to the Park position.
ion. With the wi
With the wiper
per
switch (S8 or S9) in the Low position, 12 VDC is
switch (S8 or S9) in the Low position, 12 VDC is
applied to the L terminal of the wiper motor (B9 or
applied to the L terminal of the wiper motor (B9 or
B8) for low speed
B8) for low speed.
. With the wip
With the wiper switc
er switch (S8 or
h (S8 or
S9) in the high speed position, 12 VDC is applied
S9) in the high speed position, 12 VDC is applied
to the H terminal of the wiper motor (B9 or B8) for
to the H terminal of the wiper motor (B9 or B8) for
high speed.
high speed. The wiper m
The wiper motors (B9 and B8) util
otors (B9 and B8) utilize
ize
chassis ground.
chassis ground.
Defroster Fan Motors
Defroster Fan Motors
(B2 and B4, Illustration
(B2 and B4, Illustration
6-16)
6-16)
..
The front defroster (B2) and the rear
The front defroster (B2) and the rear
defroster (B4) fan motors are controlled by
defroster (B4) fan motors are controlled by
defroster sw
defroster switch (S6).
itch (S6). Defrost
Defroster switch (S6) is
er switch (S6) is
powered by cir
powered by circuit break
cuit breaker (CB9).
er (CB9). There is a
There is a
diode between circuit breaker (CB9) and defroster
diode between circuit breaker (CB9) and defroster
switc
switch (S6).
h (S6). Its purpose i
Its purpose is to prevent an induced
s to prevent an induced
voltage generated by the defroster fan motors (B2
voltage generated by the defroster fan motors (B2
and B4), which could prolong engine shut down,
and B4), which could prolong engine shut down,
after the ignition switch (S1) is turned to the Off
after the ignition switch (S1) is turned to the Off
position.
position. With the defros
With the defroster swi
ter switch (S6) in the Low
tch (S6) in the Low
position, 12 VDC will be present on wire #40A for
position, 12 VDC will be present on wire #40A for
the front defroster motor (B2) or on wire #40 for
the front defroster motor (B2) or on wire #40 for
the rear defros
the rear defroster motor (
ter motor (B4).
B4). With the defros
With the defroster
ter
switch (S6) in the High position, 12 VDC will be
switch (S6) in the High position, 12 VDC will be
present on wire #41A for the front defroster motor
present on wire #41A for the front defroster motor
(B2) or wire #41 for the rear defroster motor (B4).
(B2) or wire #41 for the rear defroster motor (B4).
Both defroster motors (B2 and B4) utilize chassis
Both defroster motors (B2 and B4) utilize chassis
ground.
ground.
Heater Fan
Heater Fan Moto
Motorr
(B5, Illustration 6-16)
(B5, Illustration 6-16)
..
The
The
heater fan motor (B5) is controlled by heater
heater fan motor (B5) is controlled by heater
https://www.forkliftpdfmanuals.com/
