Wiper Motor; Low And High Speed Circuits; Shutting The Wiper Off; Washer Pump Operation - Pontiac Fiero 1988 Service Manual

WINDSHIELD WIPER S Y S T E M S 8E2-3
WHITE
O R A N G E
T E R M I N A L LITTERS
O N H A R N E S S
C O N N E C T O R
PARK SWITCH
MOTOR
P U R P L E
G R A Y
• M O V A B L E C O N T A C T
sw.
C O L U M N S W I T C H
2 7 7 4
Fig. 3 W i p e r Motor and S w i t c h Circuit Diagram (Non-Pulse)
Placement of a shim under the nozzle mounting
bracket will raise the pattern three degrees. Reverse
installation of the same shim will lower the pattern
three degrees. Pump and wiper motor service remain
unchanged. Shim provisions have not been provided
for the rear fluidic washer nozzles.
WIPER AND W A S H E R OPERATION
The wiper and washer operation is explained in
Fig. 4. The electronic printed circuit board controls all
the timing and washer commands. When the wash
button is pushed for more than 0.3 seconds, a demand
wash is performed in 1.5 second intervals for as long
as the button is held followed by approximately 6
seconds of dry wipes and a shut off.
Rotating the switch to either the LOW or HIGH
speed position completes the respective circuit and the
wiper motor runs at that speed.
Rotating the multi-function lever to the delay
mode operates the motor intermittently. There are five
detents, each detent is a different timed cycle. From the
low poistion the cycles are 18,10, 6, 3 and 1.25 seconds.
An instantaneous wipe can be obtained by
rotating the switch to the mist position and a
continuous wipe will be performed if the switch is held.
A circuit diagram of the wiper is shown in Figure 5.
LOW AND HIGH SPEED CIRCUITS
Moving the multi-function lever to the low or
high speed position completes the respective brush
circuit to ( + ) 12 volts DC at the multi-function lever
and the wiper motor runs at that speed.
SHUTTING THE WIPER OFF
When the wiper is turned off at the
multi-function lever, in order to have the blades stop
in their normal park position and the wiper motor shut
off properly, the motor operates in low speed. This is
accomplished as follows: with the multi-function lever
in the off position, the low speed brush circuit is
completed to ( + ) 12 volts DC at the multi-function
lever through a park switch located on the brush
assembly (terminals A and B). The park switch
contacts are normally closed and this permits the wiper
to continue to run.
When the blades reach their park position, a cam
on the large gear moves the park switch actuator that
opens the normally closed positive park switch and
grounds the wiper motor. This accomplishes a reversal
of the motor flux path which causes a no-coast positive
park, shutting off the wiper.
WASHER PUMP OPERATION
Actuating the washer portion of the
multi-function lever completes the washer pump motor
circuit to ground and mechanically moves the wiper
motor switch to the low-speed position. This dual
function starts the wiper motor and washer operation
at the same time. The washer pump runs only while the
wash switch is activated.
The washer pump consists of a permanent
magnet motor and pump assembly that is mounted in
the windshield washer container. The wiper motor can
be operated only when the ignition switch is in the run
or accessory position.
DIAGNOSIS
WINDSHIELD WIPER SYSTEM TESTER
A universal wiper system tester (tool J-25079-B
or equivalent) can be used to simplify diagnosing wiper
problems either on or off the car. A separate diagnostic
manual is distributed with the tester.
DIAGNOSTIC PROCEDURES
Fig.
6
The following procedures assume that the
technician has checked the following:
m Continuity of all harness wires
• Wiper motor-to-dash mounting screws tight
m Fuses
# Washer hoses clear
The diagnostic procedures covered in this manual
are based on certain tests and operational checks that
will help locate the problem. Prior to starting the