Windshield Washer - R/V And G-Van Models; Windshield Wiper And Washer - P-Models - GMC G Service Manual

WINDSHIELD WASHER — R/V AND
G-VAN MODELS
The washer motor is located in the bottom of the wind­
shield washer fluid reservoir. The washer is controlled by a
washer switch, which is located on the turn signal and multi­
function lever. Two wires go to the washer. The white wire
is power coming from the fuse box. The same fuse that
protects the washer motor also protects the wiper motor.
The pink wire is the ground circuit that goes through the
washer switch to ground. Refer to figures 31 and 32.
For washer diagnosis, refer to "Diagnosis of Windshield
Washer — R/V and G-Van," later in this section.
WINDSHIELD WIPER AND
WASHER — P-MODELS
The system consists of a compound wound rectangular­
shaped motor attached to a gear box containing a parking
switch in addition to the gear train. The gear train consists
of a motor armature helical gearshaft which drives an inter­
mediate gear and pinion assembly. The pinion gear of the
intermediate gear and pinion drives an output gear and
shaft assembly.
Turning the wiper switch to the LO speed position com­
pletes the circuits from the wiper terminals 1 and 3 to
ground (figure 31). Current then flows from the battery via
wiper terminal No. 2 through the series field and divides; (1)
part of the current passes through the armature to ground
via wiper terminal No. 1 to the wiper switch and (2) the
second part passes through the shunt field to ground
1. Gear Cam
2. Park Switch
(Normally Closed)
3. Terminal No. 5
4. Terminal No. 4
5. BLK w/dbl LT BLU Tracer 11. LOW Position
6. BLK 12. HIGH Position
13. Power
7. LT BLU
8. BLK 14. Ignition Switch
9. Movable Contact
15. Fuse
10. OFF Position 16. BLK w/dbl YEL Tracer
17. Terminal No. 3
Figure 29 — R/V Windshield Wiper Diagram
CAB ELECTRICAL 8A-25
through wiper terminal No. 3 to the wiper switch. The wiper
switch must be securely grounded to body metal.
Moving the wiper switch to the HI speed position opens
the shunt field circuit to ground at the switch. However, the
shunt field is connected to a 20 ohm resistor which is con­
nected across wiper terminals 1 and 3. The shunt field cur­
rent then flows via terminal No. 3 through the resistor to
terminal No. 1, to the switch, to ground.
The parking circuit covers that portion of wiper operation
when the wiper switch is turned "off" and the wiper blades
have not reached the park position.
When the wiper blades are not in the normal park posi­
tion, the parking switch contacts are still closed. The wiper
will continue to operate until the wiper output gear is turned
to a position where its cam opens the park switch. The
wiper motor circuits are completed to ground through the
parking switch.
The wiper motor must be securely grounded to body
metal.
The shunt field circuit is completed from terminal No. 3
via the switch to terminal No. 1 through the parking switch
to ground. The series field and armature circuit is also com­
pleted from terminal No. 1 through the parking switch to
ground.
The shunt field is connected direct to ground, by-passing
the resistor. This results in LO speed operation during the
parking operation.
When the output gear cam opens the park switch con­
tacts, the wiper is "off."
For diagnosis, refer to "Diagnosis of Windshield Wiper
— P-Models," later in this section.
For washer system diagnosis, refer to "Diagnosis of
Washer System — P-Models," later in this section.
! fiTlj
1 1 i » i ' i
12 11 10 " I
18. Terminal No. 2
19. Terminal No. 1
20. Circuit Breaker
Common Brush
21 .
22. High Speed Brush
23. Low Speed Brush
F-00668