Rear Wipe/Wash System Faults - Task No 10 - Monday 13th April 2015

Plan

Gather all tools and equipment required to undertake the task and retrieve vehicle information.  Record vehicle data onto Job Card.

Task Requirements

• Remove Rear Wiper Motor
• Check voltages for wipe intermittent
• Check Park Operation
• Refit Motor and Door Card
• Check Final Operation
• Complete knowledge Questions
• Complete Blog
• Report to Assessor with Analysis and Diagnosis
• Account for all tools and equipment and Tidy work area

Analysis Preliminary Checks

Battery Voltage was checked using a Voltmeter and a healthy reading was recorded.

Healthy Battery

Fuse location (Fascia 1)

I then went on to check the operation of the rear Wiper and Washers by turning on the ignition and activating the respective switch.  The washer functioned correctly, however the Rear Wiper did not, and neither did it appear to be in its' correct park position.  The respective fuse was checked firstly and proved continuity satisfactorily.  I then proceeded to remove the hatch door card in order to expose the wiper motor and associated wiring and connectors.

Wiring Diagram

I then obtained a wiring diagram of the rear wiper motor and the associated coloured wiring.  The

EP8 and Earth
wiring

diagram indicated only numbers rather than colours, however the wiring in situ were 1 Green/Yellow and two White).  The Green/Yellow was traced to EP 8 situated behind the NSR lamp cluster and proven as Earth (31).  Volt Drop on the Motor Earth return was recorded at 0.04 Volts, which is within operational parameters (0.05 Volts maximum).  The 2 white wires were otherwise identical, although through the process of elimination, one would be Battery Live (30) and the other Switched Live (15).

In order to distinguish one from the other I first activated the ignition and disconnected the connector from the motor.  I then probed the first white wire with a voltmeter which produced a constant reading of 14.42 Volts (suggesting Live Feed 30).  I then probed the second white wire which returned an initial reading of 0.0 Volts.  Upon activating the wiper switch the Voltmeter recorded a reading of 14.45 Volts (suggesting Switched Live Feed 15).

Probing 1st Wire

Probing 2nd Wire
(switch activated)

Tests thus far indicated that a live feed was reaching the connector and initially suggested a Motor failure.  I then conducted a continuity test on the Motor's 3 terminal points however, which subsequently proved the Motor as serviceable.  I then proceeded to re- conduct the tests carried out to the connector as before, only this time I could not obtain any readings whatsoever.  Upon reconnecting the connector to the motor, activating the switch and wiggling the connector wires however, the wiper briefly operated and returned to its correct park position.

Diagnosis

I currently suspect that there is either a loose or internally fractured feed wire, or possibly a problem with the connector reciprocating pins.  Due to limited time constraints the task was temporarily suspended and will be resumed in the morning.

Tuesday 14th April 2015

The ignition was re-activated and each of the feed wires retested using a Voltmeter accordingly.  Results were again intermittent.  The connector was reconnected to the motor and then manipulated whilst the switch was activated, resulting in momentary periods of correct motor operation and parking function.

Recommendation for Customer

The wiper motor is not at fault and does not require replacing.  I would suggest cutting off the connector and approximately 10 cm of attached loom, stripping back each of the 3 wires and re-testing each of the wires to ensure continuity.  A new section should then be attached, re-soldered and insulated to a new connector, and then reconnected to ensure correct operation accordingly.