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Webasto Product N.A., Inc.
38
www.techwebasto.com
CIRCUIT DIAGRAMS
DBW 2010/2020/300 COOLANT HEATERS
7.4
DBW 2020 / 300 12 V
AND
24 V -
WITH
N
OZZLE
P
REHEAT
Figure 29:
Schematic - DBW 2020 / 300 With Nozzle Preheat
BT
BATTERY
DS
INDICATOR
LIGH
T
E
IGNITION ELECTRO
D
ES
F1
FUSE 15A
F2
FUSE 20A
F3
FUSE 15A
F4
OVERHEAT FUSE
138°C
F5
FUSE 30A
F6
FUSE 15A
HR
HEATING ELEMEN
T
(fuel pre-heater)
K1
RELAY (on /
off switch)
K2
RELAY (fuel
p
re-h
eater)
L1
SOLENOID VALVE
L2
IGNITION
COIL
M1
COOLANT
CIRC
ULATION
PUMP
M2
HEATER
MOTOR
R
FLAME
DETECTOR
S1
ON
/
OFF
SWITCH
(heater)
S2
PREHEAT
(FUEL)
THERMOSTAT
(blue and b
lue wires)
S3
CONTROL
THER
MOSTAT
(green and re
d wires)
S4
TEMPERATUR
E
LIMITER
(green and g
reen wires)
X1
9-PIN HARNE
SS CONNECTOR (rou
nd)
X2
3-WAY
CONNEC
TOR
X3
2-WAY
CONNEC
TOR
BROWN
BROWN
BROWN
RED
RED
RED
BT
E
F
G
J
C
B
A
S1
D
S
F5
X
1
H
WHITE
GREEN
RED
BLACK
WHITE
WHITE
WHITE
VIOLET
F4
t°
t°
t°
WHITE
WHITE
BLACK
BLUE
VIOLET
GREEN
GREEN
GREEN
RED
ORANGE
WHITE
BROWN
BLACK
BLUE
GREEN
YELLOW
BROWN
BROWN
BROWN
BLUE
BLUE
BLACK
BLACK
GREEN
BROWN
ORANGE
GREEN
BROWN
BROWN
BROWN
BROWN
BROWN
BROWN
BROWN
RED
RED
BROWN
L
1
R
L2
E
S
4
S
3
M2
HR
S
2
K2
M
1
A
B
C
C
A
B
M
1
2
4
1
3
6
5
2
52
1
7
4
68
65
3
4
2
1
85
86
87
30
+
–
CONTROL UNIT
HEA
TER
1
2
3
45
6
2
1
1
2
3
4
5
6
7
8
BLACK
BROWN
M
BLUE
BLACK
GREEN
2
1
3
K
1
85
86
87
30
X2
F
1
F2
F3
E
F
CDAB
RED
BLUE
ORANGE
GREEN
RED
RED
F
6
A
B
ORANGE
WHITE
WHITE
D
X3