Harness Repairs
HARNESS REPAIRS
Introduction
CAUTION: The harness must be replaced when the damage is attributed to excessive current flow or where there is evidence of over-heating.
Under no circumstances should a repair be attempted to:
^ Any Media Orientated System Transport (MOST) network harnesses.
^ Supplemental Restraint System (SRS) firing circuits.
^ Link lead assemblies, which are unique to safety critical areas such as ABS and thermocouple circuits; a typical example is the ABS wheel speed sensor with moulded connector.
^ Any wires with a cross sectional area (CSA) greater than 6.0 mm.
^ Screened cables and leads.
If damage occurs to any of the above areas, an overlay harness must be used. These are available through the normal parts ordering process.
Repair Kit
^ Crimping tool.
^ Wire cutter/stripper.
^ Heat-shrink tubing.
^ Wire color identification rings.
^ Splice connectors.
^ Pre-terminated leads (connector pins with 90 mm wire 'pig tails').
^ Connector housings.
^ Connector pin extractor tools.
NOTE: Connector housings and pre-terminated leads not contained within the repair kits can be ordered from: SPX UK Ltd, Genoa House, Everdon Park, Daventry, Northants, NN11 5YJ. Tel: +44 (0)1327 303400, alternatively, contact your local SPX representative.
In order to carry out a repair, a suitable hot-air gun and heat resistant blanket will also be required (these can be sourced locally).
Part Harnesses
In addition to the items included in the harness repair kits, part harnesses are also available to effect repairs on the vehicle. These part harnesses can be viewed via 'Microcat' and are available through the normal parts ordering process.
Repair Guidelines
The Harness Repair Kit includes an illustrated instruction booklet, however the following additional repair guidelines must be followed:
Twisted Pairs
Twisted pairs of wires (CAN bus, ABS wiring, etc.) can be repaired as required. When repairing a twisted pair of wires do not unwind the existing wires any more than necessary. Before completing the repair, replicate as closely as possible the original twisting pattern on any new wiring.
Splice Connectors
It is undesirable to make more than five repair joints on the wiring to any harness connector, where more repairs are required at the same connector, the harness should be replaced.
Whenever a repair is required, the position of the splice connectors must be staggered. This keeps the bulk of the repaired area to a minimum, ensuring all trim can be refitted correctly after the repair has been effected.
Replacement Connectors
If a connector is damaged and needs replacing, use the tools contained in the Harness Repair Kit to relocate the wires into the replacement connector. Only relocate one wire at a time, ensuring it is fitted to the correct cavity in the new connector.
Gold Connector Pins
A number of vehicle connectors are fitted with gold plated pins. Do not replace gold connector pins with tin connector pins as this will lead to early failure of the electrical contact.
Repair Methods
CAUTION: Before commencing a repair, disconnect the vehicle battery and wait one minute to allow the SRS and Satellite Navigation systems time to de-energize.
The following process should be used when carrying out a repair:
NOTE: Before commencing a repair, refer to the appropriate 'Service Repair Kit' table (see example in Table 1 below) for details of the correct tools and replacement components.
The following process should be used when carrying out a repair:
1. Using the wire cutter/stripper, cut the wire to be repaired and strip the required amount of insulation from the wire.
2. Slide an appropriately sized heat shrink sleeve over the bare end wire for later use.
3. Remove the damaged connector pin from the connector housing using the appropriate extraction tools.
4. Select the correct connector pin, pre-terminated lead and fit the appropriate wire color identification rings.
5. Select the correct size of splice connector from the kit.
CAUTION: The crimping tool jaws perform two different crimps simultaneously: one crimps the wire insulation; one crimps the bare wire. Ensure the splice connector is placed correctly in the tool or the wire will be insufficiently crimped and a poor electrical contact may result.
6. The crimping tool contains three sets of jaws. The jaw colors correspond to the splice connector color. Select the correct jaw and crimp the splice connector to the harness bare-end wire.
7. Using the tool, crimp the pre-terminated lead to the splice connector.
CAUTION:
^ Place the asbestos blanket in a suitable position to avoid heat damage to adjacent components and trim.
^ Do not overheat the repair as degradation and subsequent failure of the connection may result.
8. Slide the previously fitted heat shrink sleeve into position over the splice connector. Using the hot-air gun to the manufacturer's guidelines, apply heat evenly to the heat shrink sleeve until it is tightly shrunk around the splice connector.
9. Connect the repaired wire to the connector housing.
10. Repeat steps 1 to 9 for any further damaged wires.