Troubleshooting Wiper Motor for 300Tdi Discovery
WIPERS AND WASHERS
1
FAULT DIAGNOSIS
WIPER MOTOR CHECKING
NOTE: These instructions apply to
windscreen and rear window wiper motor.
If unsatisfactory operation of wiping equipment is
experienced, a systematic check to determine fault
should be carried out:
1. Check blades for signs of excessive friction. This
reduces wiping speed of motor and cause
increased current draw which may damage
armature. Check by substitution.
2. Check windscreen wiper motor light running
current and speed with motor coupling link
disconnected from wiper shaft transmission
linkage.
Check rear window glass wiper motor with wiper
connected and glass wet. Connect an ammeter in
series with motor supply. Measure current
consumption when motor is switched on. Check
operating speed by timing speed of rotation of motor
coupling link. The results should compare with figures
given in ’General Specification Data’.
NOTE: If vehicle wiring connections are
disconnected and an alternative supply
source is applied it is essential that
correct polarity is observed. Failure to observe
this will cause motor to rotate in reverse direction,
which may result in limit switch contacts being
damaged.
3. If motor does not run satisfactorily or takes
higher than normal current, a fault exists and
must be remedied.
4. If current consumption and speed of motor are
satisfactory. A check should be carried out for
proper functioning of transmission linkage and
wiper arm shafts.
NOTE: Service parts are not available for
windscreen and rear window wiper motors
with exception of windscreen wiper rotary
connecting link.
