How to Diagnosis & Repair the Wiring Systems - Testing Buick LaCrosse I

Fastener Tightening Specifications

Fastener Tightening Specifications

Passenger Car Zoning

All grounds, in-line connectors, pass-through grommets and splices have identifying numbers that correspond to where they are located in the vehicle. The following table explains the numbering system.

Scheme 1

Vehicle Zoning Table

Electrical Symbols

Electrical Symbols OLD Symbol NEW Symbol Description Supplemental Inflatable Restraint (SIR) or Supplemental Restraint System (SRS) Icon This icon is used to alert the technician that the system contains SIR/SRS components that require certain precautions before servicing. On-Board Diagnostic (OBD II) Icon This icon is used to alert the technician that the circuit is essential for proper OBD II emission controls circuit operation. Any circuit which, if it fails, causes the malfunction indicator lamp (MIL) to turn on, is identified as an OBD II circuit. Important Icon This icon is used to alert the technician that there is additional information that will aid in servicing a system. Voltage Indicator Boxes These boxes are used on schematics to indicate when voltage is present at a fuse. Partial Component When a component is represented in a dashed box, the component or its wiring is not shown in its entirety. Entire Component When a component is represented in a solid box the component or its wiring is shown in its entirety. Fuse Circuit Breaker Fusible Link Connector Attached to Component Pigtail Connector Bolt On or Screw On Eyelet Terminal Inline Harness Connector Splice Chassis Ground Case Ground Single Filament Light Bulbs Double Filament Light Bulb Light Emitting Diodes Capacitor Battery Variable Battery Resistor Variable Resistor Position Sensor I/O Resistors I/O Switches Diode Heating Element Motor Solenoid Coil Antenna Twisted Wires Shield Switches Single Pole/Throw Relay - Normally Open Single Pole/Throw Relay - Normally Closed

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Basic Knowledge Required

Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in the service information. You should understand the basic theory of electricity, know the meaning of voltage (volts), current (amps) and resistance (ohms). You should also be able to read and understand a wiring diagram, as well as understand what happens in a circuit with an open or a shorted wire.

Checking Aftermarket Accessories

Do not connect aftermarket accessories into the following circuits

1. SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol.
2. OBD II circuits, all such circuits are indicated on circuit diagrams with the OBD II symbol.

Always check for aftermarket accessories (non-OEM) as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems.

Possible causes of vehicle problems related to aftermarket accessories include

1. Power feeds connected to points other than the battery
2. Antenna location
3. Transceiver wiring located too close to vehicle electronic modules or wiring
4. Poor shielding or poor connectors on antenna feed line
5. Check for recent service bulletins detailing installation guidelines for aftermarket accessories.

Circuit Testing

The Circuit Testing contains the following diagnostic testing information. Using this information along with the diagnostic procedures will identify the cause of the electrical malfunction.

1. «Using Connector Test Adapters»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__using-connector-test-adapters)
2. «Probing Electrical Connectors»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__probing-electrical-connectors)
3. «Troubleshooting with a Digital Multimeter»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__troubleshooting-with-a-digital-multimeter)
4. «Troubleshooting with a Test Lamp»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
5. «Using Fused Jumper Wires»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
6. «Measuring Voltage»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__measuring-voltage)
7. «Measuring Voltage Drop»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__measuring-voltage-drop)
8. «Measuring Frequency»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__measuring-frequency)
9. «Testing for Continuity»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-continuity)
10. «Testing for Short to Ground»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-short-to-ground)
11. «Testing for a Short to Voltage»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-a-short-to-voltage)
12. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
13. «Inducing Intermittent Fault Conditions»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
14. «Testing for Electrical Intermittents»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-electrical-intermittents)
15. «Scan Tool Snapshot Procedure»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
16. «Circuit Protection - Fuses»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
17. «Circuit Protection - Circuit Breakers»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-protection-circuit-breakers)
18. «Circuit Protection - Fusible Links»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-protection-fusible-links)

Using Connector Test Adapters

Note. Do not insert test equipment probes (DVOM etc.) into any connector or fuse block terminal. The diameter of the test probes will deform most terminals. A deformed terminal will cause a poor connection, which will result in a system failure. Always use the J-35616 GM-Approved Terminal Test Kit or the J 42675 Flat-Wire Probe Adapter in order to front probe terminals. Do not use paper clips or other substitutes to probe terminals. When using the J-35616 GM-Approved Terminal Test Kit, ensure the terminal test adapter choice is the correct size for the connector terminal. Do not visually choose the terminal test adapter because some connector terminal cavities may appear larger than the actual terminal in the cavity. Using a larger terminal test adapter will damage the terminal. Refer to the J-35616 GM-Approved Terminal Test Kit label on the inside of the J-35616 GM-Approved Terminal Test Kit for the correct adapter along with the connector end view for terminal size.

Probing Electrical Connectors

Frontprobe

Disconnect the connector and probe the terminals from the mating side (front) of the connector.

Note. Do not insert test equipment probes (DVOM etc.) into any connector or fuse block terminal. The diameter of the test probes will deform most terminals. A deformed terminal will cause a poor connection, which will result in a system failure. Always use the J-35616 GM-Approved Terminal Test Kit or the J 42675 Flat-Wire Probe Adapter in order to front probe terminals. Do not use paper clips or other substitutes to probe terminals. When using the J-35616 GM-Approved Terminal Test Kit, ensure the terminal test adapter choice is the correct size for the connector terminal. Do not visually choose the terminal test adapter because some connector terminal cavities may appear larger than the actual terminal in the cavity. Using a larger terminal test adapter will damage the terminal. Refer to the J-35616 GM-Approved Terminal Test Kit label on the inside of the J-35616 GM-Approved Terminal Test Kit for the correct adapter along with the connector end view for terminal size.

Refer to the following table as a guide in selecting the correct test adapter for frontprobing connectors

Probing Electrical Connectors

Backprobe

Do not disconnect the connector and probe the terminals from the harness side (back) of the connector.

Troubleshooting with a Digital Multimeter

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The J 39200 instruction manual is a good source of information and should be read thoroughly upon receipt of the DMM as well as kept on hand for future reference. See Special Tools .

A DMM should be used instead of a test lamp in order to test for voltage in high impedance circuits. While a test lamp shows whether voltage is present, a DMM indicates how much voltage is present.

The ohmmeter function on a DMM shows how much resistance exists between 2 points along a circuit. Low resistance in a circuit means good continuity.

Diodes and solid state components in a circuit can cause a DMM to display a false reading. To find out if a component is affecting a measurement take a reading once, then reverse the leads and take a second reading. If the readings differ the solid state component is affecting the measurement.

Following are examples of the various methods of connecting the DMM to the circuit to be tested

1. Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while you perform other operations or test driving. Refer to «Probing Electrical Connectors»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__probing-electrical-connectors) .
2. Disconnect the harness at both ends of the suspected circuit where it connects either to a component or to other harnesses.
3. If the system that is being diagnosed has a specified pinout or breakout box, it may be used in order to simplify connecting the DMM to the circuit or for testing multiple circuits quickly.

Tools Required

J 35616-200 Test Light - Probe Kit

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

A test lamp can simply and quickly test a low impedance circuit for voltage.

The J 35616-200 is Micro-Pack compatible and comprised of a 12-volt light bulb with an attached pair of leads.

Note. To properly operate this tool use the following procedures.

Voltage Test Procedure

1. Attach 1 lead to ground.
2. Touch the other lead to various points along the circuit where voltage should be present.
3. When the bulb illuminates, there is voltage at the point being tested.

Ground Test Procedure

1. Attach 1 lead to battery positive voltage.
2. Touch the other lead to various points along the circuit where ground should be present.
3. When the bulb illuminates, there is ground at the point being tested.

J 36169-A Fused Jumper Wire. See Special Tools .

The J 36169-A includes small clamp connectors that provide adaptation to most connectors without damage. See Special Tools . This fused jumper wire is supplied with a 20-A fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested.

Measuring Voltage

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedure measures the voltage at a selected point in a circuit.

1. Disconnect the electrical harness connector for the circuit being tested, if necessary.
2. Enable the circuit and/or system being tested. Use the following methods: Turn ON the ignition, with the engine OFF. Turn ON the engine. Turn ON the circuit and/or system with a scan tool in Output Controls. Turn ON the switch for the circuit and/or system being tested.
3. Select the V (AC) or V (DC) position on the DMM.
4. Connect the positive lead of the DMM to the point of the circuit to be tested.
5. Connect the negative lead of the DMM to a good ground.
6. The DMM displays the voltage measured at that point.

Measuring Voltage Drop

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedure determines the difference in voltage potential between 2 points.

Scheme 24

1. Set the rotary dial of the DMM to the V (DC) position.
2. Connect the positive lead of the DMM to 1 point of the circuit to be tested.
3. Connect the negative lead of the DMM to the other point of the circuit.
4. Operate the circuit.
5. The DMM displays the difference in voltage between the 2 points.

Measuring Frequency

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedure determines the frequency of a signal.

1. Apply power to the circuit.
2. Set the rotary dial of the DMM to the V (AC) position.
3. Connect the positive lead of the DMM to the circuit to be tested.
4. Connect the negative lead of the DMM to a good ground.
5. Press the Hz button on the DMM.
6. The DMM will display the frequency measured.

Testing for Continuity

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedures verify good continuity in a circuit.

With a DMM

1. Set the rotary dial of the DMM to the ohm position.
2. Disconnect the power feed (i.e. fuse, control module) from the suspect circuit.
3. Disconnect the load.
4. Press the MIN MAX button on the DMM.
5. Connect one lead of the DMM to one end of the circuit to be tested.
6. Connect the other lead of the DMM to the other end of the circuit.
7. If the DMM displays low or no resistance and a tone is heard, the circuit has good continuity.

With a Test Lamp

1. Remove the power feed (i.e. fuse, control module) from the suspect circuit.
2. Disconnect the load.
3. Connect 1 lead of the test lamp to 1 end of the circuit to be tested.
4. Connect the other lead of the test lamp to battery positive voltage.
5. Connect the other end of the circuit to ground.
6. If the test lamp illuminates (full intensity), then the circuit has good continuity.

Testing for Short to Ground

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedures test for a short to ground in a circuit.

1. Remove the power feed (i.e. fuse, control module) from the suspect circuit.
2. Disconnect the load.
3. Set the rotary dial of the DMM to the ohm position.
4. Connect 1 lead of the DMM to 1 end of the circuit to be tested.
5. Connect the other lead of the DMM to a good ground.
6. If the DMM does NOT display infinite resistance (OL), there is a short to ground in the circuit.

1. Remove the power feed (i.e. fuse, control module) from the suspect circuit.
2. Disconnect the load.
3. Connect 1 lead of the test lamp to battery positive voltage.
4. Connect the other lead of the test lamp to 1 end of the circuit to be tested.
5. If the test lamp illuminates, there is a short to ground in the circuit.

Fuse Powering Several Loads

1. Review the system schematic and locate the fuse that is open.
2. Open the first connector or switch leading from the fuse to each load.
3. Connect a DMM across the fuse terminals (be sure that the fuse is powered). When the DMM displays voltage the short is in the wiring leading to the first connector or switch. If the DMM does not display voltage refer to the next step.
4. Close each connector or switch until the DMM displays voltage in order to find which circuit is shorted.

Testing for a Short to Voltage

Note. Refer to TEST PROBE NOTICE in Cautions and Notices.

The following procedure tests for a short to voltage in a circuit.

1. Set the rotary dial of the DMM to the V (DC) position.
2. Connect the positive lead of the DMM to 1 end of the circuit to be tested.
3. Connect the negative lead of the DMM to a good ground.
4. Turn ON the ignition and operate all accessories.
5. If the voltage measured is greater than 1 volt, there is a short to voltage in the circuit.

1. J 35616 GM-Approved Terminal Test Kit
2. J-38125 Terminal Repair Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .

When the condition is not currently present, but is indicated in DTC history, the cause may be intermittent. An intermittent may also be the cause when there is a customer complaint, but the symptom cannot be duplicated. Refer to the appropriate Symptom Table of the system that is suspect of causing the condition before trying to locate an intermittent condition.

Most intermittent conditions are caused by faulty electrical connections or wiring. Inspect for the following items

1. Wiring broken inside the insulation
2. Poor connection between the male and female terminal at a connector
3. Poor terminal to wire connection-Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself and corrosion in the wire to terminal contact area, etc.
4. Pierced or damaged insulation can allow moisture to enter the wiring causing corrosion. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits.
5. Wiring which has been pinched, cut or its insulation rubbed through may cause an intermittent open or short as the bare area touches other wiring or parts of the vehicle.
6. Wiring that comes in contact with hot or exhaust components
7. Refer to «Inducing Intermittent Fault Conditions»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) in order to duplicate the conditions required, in order to verify the customer concern.
8. Refer to «Testing for Electrical Intermittents»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-electrical-intermittents) for test procedures to detect intermittent open, high resistance, short to ground and short to voltage conditions.
9. Refer to «Scan Tool Snapshot Procedure»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) for advanced intermittent diagnosis and Vehicle Data Recorder operation.

Testing for Proper Terminal Contact

It is important to test terminal contact at the component and any inline connectors before replacing a suspect component. Mating terminals must be inspected to ensure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation.

Contamination may be caused by the connector halves being improperly connected. A missing or damaged connector seal, damage to the connector itself or exposing the terminals to moisture and dirt can also cause contamination. Contamination, usually in the underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.

Deformation is caused by probing the mating side of a connector terminal without the proper adapter. Always use the J 35616 when probing connectors. Other causes of terminal deformation are improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact causing an open or intermittently open circuit.

Round Wire Connectors

Follow the procedure below to test terminal contact of Metri-Pack or 56 series terminals. Refer to the J-38125 or the J 38125-4 Instruction Manual for terminal identification. See Special Tools .

Follow the procedure below in order to test terminal contact

1. Separate the connector halves.
2. Visually inspect the connector halves for contamination. Contamination may result in a white or green build-up within the connector body or between terminals. This causes high terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body.
3. Using an equivalent male terminal from the J-38125 , test that the retention force is significantly different between a good terminal and a suspect terminal. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . Replace the female terminal in question.

Control Module/Component Voltage and Grounds

Poor voltage or ground connections can cause widely varying symptoms.

1. Test all control module voltage supply circuits. Many vehicles have multiple circuits supplying voltage to a control module. Other components in the system may have separate voltage supply circuits that may also need to be tested. Inspect connections at the module/component connectors, fuses and any intermediate connections between the voltage source and the module/component. A test lamp or a DMM may indicate that voltage is present, but neither tests the ability of the circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. Refer to «Circuit Testing»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing) and «Power Distribution Schematics»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
2. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. Refer to «Circuit Testing»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing) and «Ground Distribution Schematics»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .

Temperature Sensitivity

1. An intermittent condition may occur when a component/connection reaches normal operating temperature. The condition may occur only when the component/connection is cold or only when the component/connection is hot.
2. Freeze Frame, Failure Records, Snapshot or Vehicle Data Recorder data may help with this type of intermittent condition, where applicable.
3. If the intermittent is related to heat, review the data for a relationship with the following: High ambient temperatures Underhood/engine generated heat Circuit generated heat due to a poor connection or high electrical load Higher than normal load conditions, towing, etc.
4. If the intermittent is related to cold, review the data for the following: Low ambient temperatures-In extremely low temperatures, ice may form in a connection or component. Inspect for water intrusion. The condition only occurs on a cold start. The condition goes away when the vehicle warms up.
5. Information from the customer may help to determine if the trouble follows a pattern that is temperature related.
6. If temperature is suspected of causing an intermittent fault condition, attempt to duplicate the condition. Refer to «Inducing Intermittent Fault Conditions»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) in order to duplicate the conditions required.

Electromagnetic Interference (EMI) and Electrical Noise

Some electrical components/circuits are sensitive to electromagnetic interference (EMI) or other types of electrical noise. Inspect for the following conditions

1. A misrouted harness that is too close to high voltage/high current devices such as secondary ignition components, motors, generator etc. These components may induce electrical noise on a circuit that could interfere with normal circuit operation.
2. Electrical system interference caused by a malfunctioning relay or a control module driven solenoid or switch-These conditions can cause a sharp electrical surge. Normally, the condition will occur when the malfunctioning component is operating.
3. Improper installation of non-factory or aftermarket add on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters, alarm systems, cell phones, etc. These accessories may lead to interference while in use, but do not fail when the accessories are not in use. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__checking-aftermarket-accessories) .
4. Test for an open diode across the A/C compressor clutch and for other open diodes. Some relays may contain a clamping diode.
5. The generator may be allowing AC noise into the electrical system.

Incorrect Control Module

1. There are only a few situations where reprogramming a control module is appropriate: A new service control module is installed. A control module from another vehicle is installed. Revised software/calibration files have been released for this vehicle.
2. Verify that the control module contains the correct software/calibration. If incorrect programming is found, reprogram the control module with the most current software/calibration. Refer to «Control Module References»(/buick/lacrosse/i-2004-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) in Computer/Integrating Systems for replacement, setup and programming.

J 25070 Heat Gun

Many intermittent open or shorted circuits are affected by harness/connector movement that is caused by vibration, engine torque, bumps/rough pavement, etc. In order to duplicate the customer's concern, it may be necessary to manipulate the wiring harness if the malfunction appears to be vibration related. Manipulation of a circuit can consist of a wide variety of actions, including

1. Wiggling the harness
2. Disconnecting a connector and reconnecting
3. Stressing the mechanical connection of a connector
4. Pulling on the harness or wire in order to identify a separation/break inside the insulation
5. Relocating a harness or wires

All these actions should be performed with some goal in mind. For instance, with a scan tool connected, wiggling the wires may uncover a faulty input to the control module. The snapshot option would be appropriate here. Refer to Scan Tool Snapshot Procedure . Another option is, with the component commanded ON and OFF by the scan tool, move related connectors and wiring and observe the component operation. With the engine running, move related connectors and wiring while monitoring engine operation. If harness or connector movement affects the data displayed, component/system operation or engine operation, inspect and repair the harness/connections as necessary.

You may need to load the vehicle in order to duplicate the concern. This may require the use of weights, floorjacks, jackstands, frame machines, etc. In these cases you are attempting to duplicate the concern by manipulating the suspension or frame. This method is useful in finding harnesses that are too short and their connectors pull apart enough to cause a poor connection. A DMM set to Peak Min/Max mode and connected to the suspect circuit while testing can yield desirable results. Refer to Testing for Electrical Intermittents .

Certainly, using the senses of sight, smell and hearing while manipulating the circuit can provide good results as well.

There may be instances where circuit manipulation alone will not meet the required criteria for the fault condition to appear. In such cases it may be necessary to expose the suspect circuit to other conditions while manipulating the harness. Such conditions would include high moisture conditions, along with exceptionally high or low temperatures. The following discusses how to expose the circuit to these kinds of conditions.

Salt Water Spray

Some compounds possess the ability to conduct electricity when dissolved in water such as ordinary salt. By mixing table salt with water in sufficient quantities, you can enhance the conductive properties of water so that any circuit which may be sensitive to moisture will more readily fail when liberally sprayed with this mixture.

Mixing 0.35L (12 oz.) of water with approximately 1 tablespoon of salt will yield a salt solution of 5 percent. Fill a normal spray bottle with this mixture. This mixture is sufficient to enhance the water's own conductivity. This may cause the circuit to fail more easily when sprayed. Once the mixture is completed, spray the suspect area liberally with the solution. Then, while monitoring either a scan tool or DMM, manipulate the harness as discussed previously.

High Temperature Conditions

If the complaint tends to be heat related, you can simulate the condition using the J 25070 .

Using the heat gun, you can heat up the suspected area or component. Manipulate the harnesses under high temperature conditions while monitoring the scan tool or DMM to locate the fault condition.

The high temperature condition may be achieved simply by test driving the vehicle at normal operating temperature. If a heat gun is unavailable, consider this option to enhance your diagnosis. This option does not allow for the same control, however.

Low Temperature Conditions

Depending on the nature of the fault condition, placing a fan in front of the vehicle while the vehicle is in the shade can have the desired effect.

If this is unsuccessful, use local cooling treatments such as ice or a venturi type nozzle (one that provides hot or cold air). This type of tool is capable of producing air stream temperatures down to -18°C (0°F) from one end and +71°C (160°F) from the other. This is ideally suited for localized cooling needs.

Once the vehicle, component or harness has been sufficiently cooled, manipulate the harness or components in an effort to duplicate the concern.

Duplicating Failure Conditions

1. If none of the previous tests are successful, attempt to duplicate and/or capture the failure conditions.
2. Freeze Frame/Failure Records data, where applicable, contains the conditions that were present when the DTC set. Review and record Freeze Frame/Failure Records data. Clear the DTCs using the scan tool. Turn the key to OFF and wait 15 seconds. Operate the vehicle under the same conditions that were noted in Freeze Frame/Failure Records data, as closely as possible. The vehicle must also be operating within the Conditions for Running the DTC. Refer to Conditions for Running the DTC in the supporting text if a DTC is being diagnosed. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed.
3. An alternate method is to drive the vehicle with the DMM connected to a suspected circuit. An abnormal reading on the DMM when the concern occurs, may help you locate the concern.

Testing for Electrical Intermittents

Perform the following procedures while wiggling the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test equipment.

1. «Testing for Short to Ground»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-short-to-ground)
2. «Testing for Continuity»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-continuity)
3. «Testing for a Short to Voltage»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-a-short-to-voltage)

If the fault is not identified, perform the procedure below using the MIN MAX feature on the J 39200 DMM. See Special Tools . This feature allows you to manipulate the circuit without having to watch the J 39200 . See Special Tools . The J 39200 will generate an audible tone when a change is detected. See Special Tools .

1. Connect the J 39200 to both sides of a suspected connector (still connected) or from one end of a suspected circuit to the other. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . Refer to «Troubleshooting with a Digital Multimeter»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__troubleshooting-with-a-digital-multimeter) for information on connecting the J 39200 to the circuit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
2. Set the rotary dial of the J 39200 to the V (AC) or V (DC) position. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
3. Press the range button of the J 39200 in order to select the desired voltage range. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
4. Press the MIN MAX button of the J 39200 . See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . The J 39200 displays 100 ms RECORD and emits an audible tone (beep). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . IMPORTANT: The 100 ms RECORD mode is the length of time an input must stay at a new value in order to record the full change.
5. Simulate the condition that is potentially causing the intermittent connection, either by wiggling the connections or the wiring, test driving or performing other operations. Refer to «Inducing Intermittent Fault Conditions»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
6. Listen for the audible Min Max Alert which indicates that a new minimum or maximum value has been recorded.
7. Press the MIN MAX button once in order to display the MAX value and note the value.
8. Press the MIN MAX button again in order to display the MIN value and note the value.
9. Determine the difference between the MIN and MAX values. If the variation between the recorded MIN and MAX voltage values is 1 volt or greater an intermittent open or high resistance condition exists. Repair the condition as necessary. If the variation between the recorded MIN and MAX voltage values is less than 1 volt an intermittent open or high resistance condition does not exist.

J 42598 Vehicle Data Recorder. See Special Tools .

Snapshot is a recording of the parameters of a control module while the snapshot is being made. A snapshot may be used to analyze the data during the time a vehicle condition is current. This allows you to concentrate on making the condition recur, rather than trying to view all the data in anticipation of the fault. The snapshot contains information around a trigger point that you have determined.

There are many different scan tools that have varying functions. For example, the Tech 2 Scan Tool can also graph parameters separately or in combinations of parameters for comparison. Only a single data list may be recorded in each snapshot. It can trigger a Snapshot manually at the time the symptom is noticed or be set up in advance to trigger when a DTC sets. The Tech 2 Scan Tool has the ability to store 2 snapshots. The ability to record 2 snapshots allows comparing hot versus cold and good versus bad vehicle scenarios. The snapshots are stored on a first-in, first-out basis. If a third snapshot is taken, the first snapshot stored in the memory will be lost.

Snapshots can be 1 of 2 types

1. Snapshot-taken from the Snapshot menu choice
2. Quick Snapshot-taken from the Data Display soft key choice, does not contain DTC information

When a snapshot is taken, it is recorded on the memory card and may contain as many as 1,200 frames of information. Because the snapshot is recorded onto the memory card, snapshots are not lost if the Tech 2 Scan Tool is powered down.

The snapshot replay screen has a plot soft key that can be of great value for intermittent diagnosis. The snapshot plot feature can help you to quickly determine if a sensor is outside of its expected values by plotting 3 parameters at a time. The data will be displayed both graphically and numerically showing the minimum and maximum values for all frames captured. This is helpful, especially if the fault occurs only once and does not set a DTC.

Vehicle Data Recorder

The J 42598 is connected to the data link connector (DLC) and sent with the customer. See Special Tools . The J 42598 captures data for later retrieval and analysis by the technician. See Special Tools . Refer to the vehicle data recorder user instructions for more information.

Scheme 25

The fuse is the most common method of an automotive wiring circuit protection. Whenever there is an excessive amount of current flowing through a circuit the fusible element will melt and create an open or incomplete circuit. Fuses are an one time protection device and must be replaced each time the circuit is overloaded. To determine if a fuse is open, remove the suspected fuse and examine the element in the fuse for an open (2). If not broken (1), also check for continuity using a DMM or a continuity tester. If the element is open or continuity is suspect, replace the fuse with one of equal current rating.

Fuse Types

Circuit Protection - Circuit Breakers

A circuit breaker is a protective device that is designed to open the circuit when a current load is in excess of the rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. Two types of circuit breakers are used.

Circuit Protection - Fusible Links

Fusible link is wire designed to melt and break continuity when excessive current is applied. It is often located between or near the battery and starter or electrical center. Use a continuity tester or a DMM at each end of the wire containing the fusible link in order to determine if it is broken. If broken, it must be replaced with fusible link of the same gage size.

Repairing a Fusible Link

Refer to Splicing Copper Wire Using Splice Clips .

Wiring Repairs

The Wiring Repairs contains the following types of wiring repair information. Using these elements together will make wiring repair faster and easier

1. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
2. «Flat Wire Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__flat-wire-repairs)
3. «GMLAN Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
4. «High Temperature Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
5. «Heated Oxygen Sensor (HO2S) Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
6. «Splicing Copper Wire Using Splice Clips»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__splicing-copper-wire-using-splice-clips)
7. «Splicing Copper Wire Using Splice Sleeves»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
8. «Splicing Twisted or Shielded Cable»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__splicing-twisted-or-shielded-cable)
9. «Splicing Inline Harness Diodes»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__splicing-inline-harness-diodes)
10. «SIR/SRS Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

Repairing Damaged Wire Insulation

If the conductive portion of the wire is not damaged, locate the problem and apply tape around the wire. If the damage is more extensive, replace the faulty segment of the wire. Refer to Splicing Copper Wire Using Splice Clips and follow the instruction to repair the wire.

Wire Size Conversion

Flat Wire Repairs

Note. The flat wire within the flex wiring harness is not serviceable. If an open or short exists within the flex wiring harness the complete harness must be replaced.

J-38125 Terminal Repair Kit. See Special Tools .

The GM Local Area Network (GMLAN) System requires special wiring repair procedures due to the sensitive nature of the circuitry. Follow the specific procedures and instructions when working on GMLAN connectors and terminals.

The tool kit J-38125 contains the following items in order to repair the GMLAN wiring. See Special Tools .

1. DuraSeal splice sleeves
2. A wire stripping tool
3. J 38125-8 Crimping Tool (GM P/N 12085115)
4. J 38125-5 Ultra Torch Special Tool (GM P/N 12085116)

The DuraSeal splice sleeves have the following 2 critical features

1. A special heat shrink sleeve environmentally seals the splice. The heat shrink sleeve contains a sealing adhesive inside.
2. A cross hatched (knurled) core crimp provides necessary contact integrity for the sensitive, low energy circuits.

The J-38125 also serves as a generic terminal repair kit. See Special Tools . The kit contains the following items

1. A large sampling of common electrical terminals
2. The correct tools in order to attach the terminals to the wires
3. The correct tools in order to remove the terminals from the connectors

GMLAN Repairs

GMLAN has 2 types of networks, low speed and high speed. Low speed GMLAN has a single wire and works at slow speeds. High speed GMLAN has 2 wires in a twisted pair and works at higher speeds. For more information on GMLAN, refer to Data Link Communications Description and Operation .

GMLAN Connector Terminal Repair

The terminals in the GMLAN system are made of a special metal. This metal provides the necessary contact integrity for the sensitive, low energy circuits. These terminals are available in the J-38125 . See Special Tools . If the individual terminals are damaged on any GMLAN connection, use the appropriate connector repair procedure in order to repair the terminal. Refer to Connector Repairs for the appropriate connector repair procedure.

GMLAN Wire Repair

If a wire is damaged, repair the wire by splicing in a new section of wire of the same gage size (0.5 mm, 0.8 mm, 1.0 mm, etc.). Use the DuraSeal splice sleeves and splice crimping tool from the J-38125 . See Special Tools . Use the following wiring repair procedures in order to ensure the integrity of the sealed splice.

GMLAN Wiring Repairs

1. Open the harness by removing any tape: Use a sewing seam ripper (available from sewing supply stores) in order to cut open the harness in order to avoid wire insulation damage. Use the DuraSeal splice sleeves on all types of insulation except coaxial. Do not use the DuraSeal splice sleeve to form a splice with more than 2 wires coming together.
2. Cut as little wire off the harness as possible. You may need the extra length of wire in order to change the location of a splice. Adjust splice locations so that each splice is at least 40 mm (1.5 in) away from the other splices, harness branches or connectors.
3. Strip the insulation: When adding a length of wire to the existing harness, use the same size wire as the original wire. Perform one of the following items in order to find the correct wire size: Find the wire on the schematic and convert the metric size to the equivalent American wire gage (AWG) size. Use an AWG wire gage. If you are unsure of the wire size, begin with the largest opening in the wire stripper and work down until achieving a clean strip of the insulation. Strip approximately 7.5 mm (0.313 in) of insulation from each wire to be spliced. Do not nick or cut any of the strands. Inspect the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section.
4. Select the proper DuraSeal splice sleeve according to the wire size. Refer to «GMLAN Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) at the beginning of the repair procedure for the color coding of the DuraSeal splice sleeves and the crimp tool nests.
5. Use the Splice Crimp Tool from the J-38125 in order to position the DuraSeal splice sleeve in the proper color nest of the Splice Crimp Tool. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . The crimp tool has three nests, 1 is for the salmon and green splice sleeve, 2 is for the blue splice sleeve and 3 is for the yellow splice sleeve.
6. Place the DuraSeal splice sleeve in the nest. Ensure that the crimp falls midway between the end of the barrel and the stop. The sleeve has a stop (3) in the middle of the barrel (2) in order to prevent the wire (1) from going further. Close the hand crimper handles slightly in order to firmly hold the DuraSeal splice sleeve in the proper nest.
7. Insert the wire into the splice sleeve barrel until the wire hits the barrel stop.
8. Tightly close the handles of the crimp tool until the crimper handles open when released. The crimper handles will not open until you apply the proper amount of pressure to the splice sleeve. Repeat steps 4 and 5 for the opposite end of the splice.
9. Using the heat torch, apply heat to the crimped area of the barrel.
10. Start in the middle and gradually move the heat barrel to the open ends of the tubing: The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

J-38125 Terminal Repair Kit. See Special Tools .

High Temperature Wiring

Wiring that is exposed to high temperatures, 135°C (275°F) or higher, for prolonged periods of time may use materials i.e. wires, connectors and shielding that has a higher heat rating than typical wiring. When making a repair in a high temperature area observe the following

1. Use high temperature bulk wire rated at 150°C (302°F) continuous temperature to replace any damaged wire.
2. Replace any heat shielding that is removed.
3. Cover any DuraSeal splice sleeves with SCT1 shrink tubing (available in the J-38125 Terminal Repair kit).
4. After making a wiring repair, ensure that the location of the wiring is not moved closer to the heat source.

Identifying High Temperature Wiring

Wiring that is exposed to high temperature, 135°C (275°F) or higher, for prolonged periods of time need special considerations when making wiring repairs. Areas that may be exposed to higher temperatures can be identified by heat resistant materials that are being used in those areas. These materials may include heat reflective tape, moon tape and high temperature shrink tubing. Also conduit and other protective coverings may be used. Because conduit or similar coverings are used throughout the vehicle regardless of the temperature, it may be necessary for the technician to determine if an area is exposed to excessive heat before making a wiring repair. Obvious areas of consideration would be any area located near the exhaust manifolds, catalytic converter and exhaust pipes.

The J-38125 contains much of the material you will need to perform repairs on areas exposed to high heat. See Special Tools . The kit contains the following items

1. DuraSeal splice sleeves to crimp and seal connections
2. High temperature SCT1 shrink tubing to protect the splice sleeves
3. A large sampling of common electrical terminals
4. The correct crimp tool to attach the terminals to the wires
5. The correct tools to remove the terminals from the connectors

The J-38125 does not contain wire that is suitable to high temperature exposure. See Special Tools . Use high temperature bulk wire rated at 150°C (302°F) continuous temperature of the same or larger gage size as the original wire when repair damage wire. Also replace any reflective tape that you remove during the repair.

High Temperature Wire Repair

If any wire except the pigtail is damaged, repair the wire by splicing in a new section of wire rated at 150°C (302°F) continuous temperature rating of the same gage size (0.5 mm, 0.8 mm, 1.0 mm etc.). Use the DuraSeal splice sleeves and splice crimping tool from the J-38125 and then encapsulate the splice sleeve using the high temperature SCT1 shrink tubing. See Special Tools . Use the following wiring repair procedures in order to ensure the integrity of the sealed splice.

High Temperature Wiring Repairs

1. Open the harness by removing any tape.
2. Use a sewing seam ripper, available from sewing supply stores, in order to cut open the harness in order to avoid wire insulation damage.
3. Cut as little wire off the harness as possible. You may need the extra length of wire in order to change the location of a splice. Adjust splice locations so that each splice is at least 40 mm (1.5 in) away from the other splices, harness branches or connectors.
4. Strip the insulation: When adding a length of wire to the existing harness, use the same size wire as the original wire. Perform one of the following items in order to find the correct wire size: Find the wire on the schematic and convert the metric size to the equivalent American wire gage (AWG) size. Use an AWG wire gage. If you are unsure of the wire size, begin with the largest opening in the wire stripper and work down until achieving a clean strip of the insulation. Strip approximately 7.5 mm (0.313 in) of insulation from each wire to be spliced. Do not nick or cut any of the strands. Inspect the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section.
5. Slide a section of high temperature SCT1 shrink tubing down the length of wire to be spliced. Ensure that the shrink tubing will not interfere with the splice procedure.
6. Select the proper DuraSeal splice sleeve according to the wire size. Refer to «High Temperature Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) at the beginning of the repair procedure for the color coding of the DuraSeal splice sleeves and the crimp tool nests.
7. Use the Splice Crimp Tool from the J-38125 in order to position the DuraSeal splice sleeve in the proper color nest of the Splice Crimp Tool. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . The crimp tool has three nests, 1 is for the salmon and green splice sleeve, 2 is for the blue splice sleeve and 3 is for the yellow splice sleeve.
8. Place the DuraSeal splice sleeve in the nest. Ensure that the crimp falls midway between the end of the barrel and the stop. The sleeve has a stop (3) in the middle of the barrel (2) in order to prevent the wire (1) from going further. Close the hand crimper handles slightly in order to firmly hold the DuraSeal splice sleeve in the proper nest.
9. Insert the wire into the DuraSeal splice sleeve barrel until the wire hits the barrel stop.
10. Tightly close the handles of the crimp tool until the crimper handles open when released. The crimper handles will not open until you apply the proper amount of pressure to the splice sleeve. Repeat steps 4 and 5 for the opposite end of the splice.
11. Using the heat torch, apply heat to the crimped area of the barrel.
12. Gradually move the heat barrel to the open end of the tubing: The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.
13. Center the high temperature SCT1 shrink tube over the DuraSeal splice sleeve.
14. Using the heat torch, apply heat to the high temperature heat shrink tubing.
15. Gradually move the heat from the center to the open end of the tubing: The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.
16. Replace any reflective tape and clips that may have been remove during the repair.

J-38125 Terminal Repair Kit. See Special Tools .

Procedure

Note. Do not solder repairs under any circumstances as this could result in the air reference being obstructed.

If the heated oxygen sensor pigtail wiring, connector or terminal is damaged the entire oxygen sensor assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly it must have a clean air reference. This clean air reference is obtained by way of the oxygen sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degrade oxygen sensor performance.

The following guidelines should be used when servicing the heated oxygen sensor

1. Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor, causing poor performance. Also, the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems.
2. Neither the sensor nor vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire.
3. Do not remove or defeat the oxygen sensor ground wire (where applicable). Vehicles that utilize the ground wire sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance.
4. To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector.

The engine harness may be repaired using the J-38125 . See Special Tools .

Splicing Copper Wire Using Splice Clips

J-38125 Terminal Repair Kit. See Special Tools .

Splicing Procedure

1. Open the harness. If the harness is taped, remove the tape. To avoid wiring insulation damage, use a sewing ripper in order to cut open the harness. If the harness has a black plastic conduit, pull out the desired wire.
2. Cut the wire. Cut as little wire off the harness as possible. Ensure that each splice is at least 40 mm (1.5 in) away from other splices, harness branches and connectors. This helps prevent moisture from bridging adjacent splices and causing damage.
3. Select the proper size and type of wire. The wire must be of equal or greater size than the original (except fusible link). The wire's insulation must have the same or higher temperature rating. Use general purpose insulation for areas that are not subject to high temperatures. Use a cross-linked polyethylene insulated wire for areas where high temperatures are expected. IMPORTANT: Use cross-linked polyethylene wire to replace PVC, but do not replace cross-linked polyethylene with PVC. Cross-linked polyethylene wire is not fuel resistant. Do not use to replace wire where there is the possibility of fuel contact.
4. Strip the insulation. Select the correct size opening in the wire stripper or work down from the largest size. Strip approximately 7.5 mm (5/16 in) of insulation from each wire to be spliced.
5. Select the proper clip to secure the splice. Follow the instructions in the J-38125 in order to determine the proper clip size crimp tool and anvil. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
6. Overlap the 2 stripped wire ends and hold them between thumb and forefinger.
7. Center the splice clip (2) over the stripped wires (1) and hold the clip in place. Ensure that the wires extend beyond the clip in each direction. Ensure that no insulation is caught under the clip.
8. Center the crimp tool over the splice clip and wires.
9. Apply steady pressure until the crimp tool closes. Ensure that no strands of wire are cut.
10. Crimp the splice on each end (2).
11. Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instructions for the solder equipment.
12. Tape the splice. Roll on enough tape in order to duplicate the thickness of the insulation on the existing wires.
13. Additional tape can be applied to the wire if the wire does not belong in a conduit or another harness covering. Use a winding motion in order to cover the first piece of tape.

J-38125 Terminal Repair Kit. See Special Tools .

Use duraseal splice sleeves to form a one-to-one splice on all types of insulation except tefzel and coaxial. Use duraseal splice sleeves where there is special requirements such as moisture sealing. Follow the instructions below in order to splice copper wire using duraseal splice sleeves.

Splicing Copper Wire Using Splice Sleeves

1. Open the harness. If the harness is taped, remove the tape. To avoid wiring insulation damage, use a sewing ripper in order to cut open the harness. If the harness has a black plastic conduit, pull out the desired wire.
2. Cut the wire. Cut as little wire off the harness as possible. Ensure that each splice is at least 40 mm (1.5 in) away from other splices, harness branches and connectors. This helps prevent moisture from bridging adjacent splices and causing damage.
3. Select the proper size and type of wire. The wire must be of equal or greater size than the original. The wires insulation must have the same or higher temperature rating (4). Use general purpose insulation for areas that are not subject to high temperatures. Use a cross-linked polyethylene insulated wire for areas where high temperatures are expected. IMPORTANT: Use cross-linked polyethylene wire to replace PVC, but do not replace cross-linked polyethylene with PVC. Cross-linked polyethylene wire is not fuel resistant. Do not use to replace wire where there is the possibility of fuel contact.
4. Strip the insulation. Select the correct size opening in the wire stripper or work down from the largest size. Strip approximately 7.5 mm (5/16 in) of insulation from each wire to be spliced (1).
5. Select the proper duraseal splice sleeve (2) and the required crimp nest tool. Refer to «Splicing Copper Wire Using Splice Sleeves»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
6. Place the duraseal splice sleeve in the J-38125-8 (GM P/N 12085115) crimp tool nest so that the crimp falls at point 1 on the splice.
7. Close the hand crimper handles slightly in order to hold the duraseal splice sleeve firmly in the proper crimp tool nest.
8. Insert the wires into the duraseal splice sleeve until the wire hits the barrel stop. The splice sleeve has a stop in the middle of the barrel in order to prevent the wire from passing through the splice (3).
9. Close the handles of the J-38125-8 (GM P/N 12085115), until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve.
10. Shrink the insulation around the splice. Using the heat torch, apply heat to the crimped area of the barrel. Gradually move the heat barrel to the open end of the tubing. The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

Splicing Twisted or Shielded Cable

Twisted/shielded cable is used in order to protect wiring from electrical noise. Two-conductor cable of this construction is used between the radio and the Delco-Bose® speaker/amplifier units and other applications where low level, sensitive signals must be carried. Follow the instructions below in order to repair the twisted/shielded cable.

1. Remove the outer jacket (1). Use care not to cut into the drain wire of the mylar tape.
2. Unwrap the tape. Do not remove the tape. Use the tape in order to rewrap the twisted conductors after the splice is made.
3. Prepare the splice. Untwist the conductors and follow the splicing instructions for copper wire. Staggering the splices by 65 mm (2.5 in) is recommended.
4. Re-assemble the cable. Rewrap the conductors with the mylar tape. Use caution not to wrap the drain wire in the tape (1). Follow the splicing instructions for copper wire and splice the drain wire. Wrap the drain wire around the conductors and tape with mylar tape.
5. Tape over the entire cable. Use a winding motion when you apply the tape.

Splicing Inline Harness Diodes

Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode use the following procedure.

1. Open the harness. If the harness is taped, remove the tape. To avoid wiring insulation damage, use a sewing ripper in order to cut open the harness. If the harness has a black plastic conduit, pull out the diode.
2. If the diode is taped to the harness, remove all of the tape.
3. Check and record the current flow direction and orientation of diode.
4. Remove the inoperative diode from the harness with a suitable soldering tool. IMPORTANT: If the diode is located next to a connector terminal remove the terminal(s) from the connector to prevent damage from the soldering tool.
5. Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode.
6. Check current flow direction of the new diode, being sure to install the diode with correct bias. Reference the appropriate service information wiring schematic to obtain the correct diode installation position.
7. Attach the new diode to the wire(s) using 60/40 rosin core solder. Before soldering attach some heat sinks (aluminum alligator clips) across the diode wire ends to protect the diode from excessive heat. Follow the manufacturer's instruction for the soldering equipment.
8. Reinstall terminal(s) into the connector body if previously removed.
9. Tape the diode to the harness or connector using electrical tape.

J-38125 Terminal Repair Kit. See Special Tools .

The Supplemental Inflatable Restraint (SIR) System/Supplemental Restraint System (SRS) requires special wiring repair procedures due to the sensitive nature of the circuitry. Follow the specific procedures and instructions when working with the SIR/SRS and the wiring components, such as connectors and terminals.

The tool kit J-38125 contains the following items. See Special Tools .

1. DuraSeal splice sleeves, in order to repair the SIR/SRS wiring
2. A wire stripping tool
3. A special crimping tool
4. A heat torch
5. Instruction information

The DuraSeal splice sleeves have the following 2 critical features

1. A special heat shrink sleeve environmentally seals the splice. The heat shrink sleeve contains a sealing adhesive inside.
2. A cross hatched (knurled) core crimp provides necessary contact integrity for the sensitive, low energy circuits.

The J-38125 also serves as a generic terminal repair kit. See Special Tools . The kit contains the following items

1. A large sampling of common electrical terminals
2. The correct tools in order to attach the terminals to the wires
3. The correct tools in order to remove the terminals from the connectors

SIR/SRS Connector Repair (Plastic Body and Terminal Metal Pin)

Use the connector repair assembly packs in order to repair the damaged SIR/SRS wire harness connectors and the terminals. Do not use the connector repair assembly pack in order to repair the pigtails. These kits include an instruction sheet and the DuraSeal splice sleeves. Use the DuraSeal splice sleeves in order to splice the new wires, connectors and terminals to the harness. The splice crimping tool is color keyed in order to match the splices from the J-38125 . See Special Tools . You must use the splice crimping tool in order to apply these splices.

The terminals in the SIR/SRS are made of a special metal. This metal provides the necessary contact integrity for the sensitive, low energy circuits. These terminals are only available in the connector repair assembly packs. Do not substitute any other terminals for those in the assembly packs.

If the individual terminals are damaged on the sensing and diagnostic module (SDM) harness connector, use one of the following 2 components in order to replace the SDM harness connector

1. The SDM harness connector pigtail assembly
2. The SDM harness connector replacement kit

If the individual terminals are damaged on any other SIR/SRS connection, use the appropriate connector repair assembly pack in order to replace the entire connection. Replace the entire SIR/SRS wiring harness, if needed, in order to maintain SIR/SRS circuit integrity.

SIR/SRS Wire Pigtail Repair

A wire pigtail is a wire or wires attached directly to the device, not by a connector. If a wiring pigtail is damaged, you must replace the entire component, with pigtail. The inflatable restraint steering wheel module coil is an example of a pigtail component.

SIR/SRS Wire Repair

If any wire except the pigtail is damaged, repair the wire by splicing in a new section of wire of the same gage size (0.5 mm, 0.8 mm, 1.0 mm etc.). Use the DuraSeal splice sleeves and splice crimping tool from the J-38125 . See Special Tools . Use the following wiring repair procedures in order to ensure the integrity of the DuraSeal splice sleeves.

SIR/SRS Wiring Repairs

1. Open the harness by removing any tape: Use a sewing seam ripper, available from sewing supply stores, in order to cut open the harness in order to avoid wire insulation damage. Use the DuraSeal splice sleeves on all types of insulation except tefzel and coaxial. Do not use the crimp and DuraSeal splice sleeve to form a splice with more than 2 wires coming together.
2. Cut as little wire off the harness as possible. You may need the extra length of wire in order to change the location of a splice. Adjust splice locations so that each splice is at least 40 mm (1.5 in) away from the other splices, harness branches or connectors.
3. Strip the insulation: When adding a length of wire to the existing harness, use the same size wire as the original wire. Perform one of the following items in order to find the correct wire size: Find the wire on the schematic and convert the metric size to the equivalent AWG size. Use an AWG wire gage. If you are unsure of the wire size, begin with the largest opening in the wire stripper and work down until achieving a clean strip of the insulation. Strip approximately 7.5 mm (0.313 in) of insulation from each wire to be spliced. Do not nick or cut any of the strands. Inspect the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section.
4. Select the proper DuraSeal splice sleeve according to the wire size. Refer to «SIR/SRS Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) the above table at the beginning of the repair procedure for the color coding of the DuraSeal splice sleeves and the crimp tool nests.
5. Use the Splice Crimp Tool from the J-38125 to crimp DuraSeal splice sleeve. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) . In order to position the DuraSeal splice sleeve in the proper color nest of the Splice Crimp Tool. The crimp tool has three nests, 1 is for the salmon and green splice sleeve, 2 is for the blue splice sleeve and 3 is for the yellow splice sleeve.
6. Place the DuraSeal splice sleeve in the nest. Ensure that the crimp falls midway between the end of the barrel and the stop. The sleeve has a stop (3) in the middle of the barrel (2) in order to prevent the wire (1) from going further. Close the hand crimper handles slightly in order to firmly hold the DuraSeal splice sleeve in the proper nest.
7. Insert the wire into the splice sleeve barrel until the wire hits the barrel stop.
8. Tightly close the handles of the crimp tool until the crimper handles open when released. The crimper handles will not open until you apply the proper amount of pressure to the DuraSeal splice sleeve. Repeat steps 4 and 5 for the opposite end of the splice.
9. Using the heat torch, apply heat to the crimped area of the barrel.
10. Gradually move the heat barrel to the open end of the tubing: The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage is achieved.

SIR/SRS System Wire Splice Repair

Apply a new splice, not sealed, from the J-38125 if damage occurs to any of the original equipment splices (3 wires or more) in the SIR/SRS wiring harness. See Special Tools . Carefully follow the instructions included in the kit for proper splice clip application.

Connector Position Assurance (CPA)

The connector position assurance (CPA) is a small plastic insert that fits through the locking tabs of a connector. CPAs are used in all SIR System connectors and also in some connectors of other systems. The CPA ensures that the connector halves cannot vibrate apart. You must have the CPA in place in order to ensure good contact between the mating terminals of a connection.

Terminal Position Assurance (TPA)

The terminal position assurance (TPA) insert resembles the plastic combs used in the control module connectors. The TPA keeps the terminal securely seated in the connector body. Do not remove the TPA from the connector body unless you remove a terminal for replacement.

Connector Repairs

Connector Repairs contains a list of all connector repairs in Wiring Systems. The connector repairs are listed by the connector manufacturer and then by connector type. If the technician cannot identify the manufacturer of the connector, refer to Identifying Connectors . Knowing the connector manufacturer will assist in finding the correct connector repair from the following list

1. «Connector Position Assurance Locks»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-position-assurance-locks)
2. «Terminal Position Assurance Locks»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__terminal-position-assurance-locks)
3. «Bosch Connectors (BSK)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Bosch Connectors (0.64)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Bosch Connectors (2.8 JPT)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
4. «Delphi Connectors (Weather Pack)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Delphi Connectors (Push To Seat)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Delphi Connectors (Pull To Seat)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Delphi Connectors (Micro-Pack 100W)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Delphi Connectors (Micro .64)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
5. «Tyco/AMP Connectors (CM 42-Way)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Tyco/AMP Connectors (Sensor)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) or «Tyco/AMP Connectors (025 Cap)»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
6. «Yazaki Connectors»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)
7. «Repairing Connector Terminals»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

Identifying Connectors

Knowing the connector manufacturer is helpful when trying to locating the correct connector repair procedure. There are many different connector designs used on GM vehicles and it is sometimes difficult to identify the connector manufacturer. The information in this document should help with the identification of connector manufactures.

The following connector manufacturers make most of the connectors found in GM vehicles

1. AFL/EPC (Alcoa Fujikura Ltd./Engineered Plastics Components)
2. Bosch
3. Delphi
4. FCI (Framatome Connectors International)
5. JAE (Japan Aviation Electronics)
6. JST (Japan Solderless Terminals)
7. Kostel
8. Molex
9. Sumitomo
10. Tyco/AMP
11. Yazaki

Identifying the manufacturer of a connector is often difficult. When trying to determine the manufacturer of a connector, look for specific identifying marks that are unique to that connector supplier. Most of these identify marks are hard to find or see. Check the connector carefully and refer to the following information for pictures and descriptions of connector identification markings.

1. Most of AFLs connectors have EPC on their connector body. Some of the smaller connectors will not have any markings on them.
2. In some cases Bosch will actually be printed on the connector. If Bosch does not appear on the connector, look for the Bosch logo. The Bosch logo is a circle with a blunted arrow inside. This logo can appear anywhere on the connector and is often very small.
3. In some cases Delphi will actually be printed on the connector. If Delphi is not printed on the connector, look for PED. In both cases there is no specific orientation for Delphi or PED and they can appear anywhere on the connector.
4. FCI connectors may have the FCI logo on their connectors. The logo is the letters FCI with an "A" above it.
5. JAE connector have JAE in small letters on their connectors.
6. JST connectors have JST in small letters on their connectors, similar to that above. The location of the logo will vary with the connector size and style.
7. Kostel has a "K" with a circle around it. These connector are usually used as a transmissions connection and are currently use on some Cadillac vehicles.
8. Most Molex connectors will have the Molex logo on the dresscover of the connector. In some cases the connectors may have MX followed by another letter. The third letter indicates where the connector was made. A connector with MXD is a Molex connector made in Detroit. Sumitomo has a unique symbol on their connector and possibly a part number. The symbol is similar to that of a diamond lying on its side, similar to that shown. The logo could appear anywhere but the most common place is at the wire side of the housing.
9. Tyco/AMP has many different and unique connector designs. Some may or may not have identifiable marks on them.
10. Yazaki has a wedge or arrow shape, similar to that shown.

Connector Position Assurance Locks

The connector position assurance (CPA) is a small plastic insert that fits through the locking tabs of the connector. CPAs are used in various connectors throughout the vehicle. CPAs are also used in all SIR system electrical connectors. The CPA ensures that the connector halves cannot vibrate apart. You must have the CPA in place in order to ensure good contact between the mating terminals, of the connector.

Terminal Position Assurance Locks

The terminal position assurance (TPA) insert resembles the plastic combs used in the control module connectors. The TPA keeps the terminal securely seated in the connector body. Do not remove the TPA from the connector body unless you remove a terminal for replacement.

J-38125 Terminal Repair Kit. See Special Tools .

Terminal Removal Procedure

1. Disconnect the connector from the component.
2. Remove the wire dress cover, if necessary.
3. Push the wire side of the terminal that is being removed toward the connector and hold it in position.
4. Insert the J 38125-561 tool into the 2 cavities on each side of the terminal at the front of the connector and push until you feel the tool disengage the terminal retainers. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
5. Carefully pull the terminal out of the connector. Always remember never use force when pulling a terminal out of a connector. If the terminal is difficult to remove, repeat the entire procedure.

Terminal Repair Procedure

Use the appropriate terminal and follow the instructions in the J-38125 . See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

1. Locate the lever lock on the wire dress cover. While pressing the lock, pull the lever over and past the lock until the lever is at the end of its travel.
2. Disconnect the connector from the component.
3. Pull the rubber boot that covers the wires back to expose the end of the connector dress cover.
4. Place the connector locking lever in the center of the connector.
5. Locate the 2 dress cover locking tabs that are on the wire end of the connector. Insert a small flat-bladed tool between the cover and connector body and pry up.
6. Locate the 2 dress cover locking tabs located on the opposite side of the connector. Insert a small flat-bladed tool between the cover at the connector end and pry up.
7. Remove the dress cover.
8. Cut the tie wrap on the wire bundle.
9. Remove the terminal position assurance (TPA) by inserting a small flat-bladed tool into the small slot in the end of the slider and pushing on the TPA until it comes out of the connector. When the TPA exits the opposite side of the connector, gasp the TPA and pull it completely out of the connector.
10. Push the wire side of the terminal that is being removed toward the connector and hold it in position.
11. Insert the J 38125-560 (GM P/N 15314260) into the 2 triangular cavities on each side of the terminal at the front of the connector. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
12. Carefully pull the terminal out of the connector. Always remember never use force when pulling a terminal out of a connector. If the terminal is difficult to remove, repeat the entire procedure.

Use the appropriate terminal and follow the instructions in the J-38125 . See Special Tools .

Terminal Replacement Procedure

1. Never insert the same terminal back into the connector once it is removed. Crimp on a new terminal.
2. Prior to installation the terminal must be aligned so the (1) coding lugs align with the (2) coding grooves on the connector.
3. Once the terminal is aligned, slide the terminal into the cavity until the retainer has engaged in the cavity of the connector.
4. Slide the TPA in the connector body and seat it using a small flat bladed tool. The TPA is seated when it is flush with the contact housing.
5. Secure the wires to the connector body using a tie wrap and replace the dress cover and grommet.

J-38125 Terminal Repair Kit. See Special Tools .

1. Pull out the slider on the connector position assurance (CPA) until it is at the end of its travel.
2. Disconnect the connector from the component.
3. Remove the wire dress cover, if necessary.
4. Push the wire side of the terminal that is being removed toward the connector and hold it in position.
5. Insert the J 38125-557 (GM P/N 12122378) into the 2 cavities on each side of the terminal at the front of the connector and push until you feel the tool disengage the terminal retainers. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
6. Carefully pull the terminal out of the connector. Always remember never use force when pulling a terminal out of a connector. If the terminal is difficult to remove, repeat the entire procedure.

Use the appropriate terminal and follow the instructions in the J-38125 . See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

The following is the proper procedure for the repair of Weather Pack® Connectors.

1. Separate the connector halves (1).
2. Open the secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector (1).
3. Grasp the wire and push the terminal to the forward most position. Hold the wire in this position.
4. Insert the Weather Pack® terminal removal tool J 38125-10A (GM P/N 12014012-1) into the front (mating end) of the connector cavity until it rests on the cavity shoulder (1).
5. Gently pull on the wire to remove the terminal through the back of the connector (2). IMPORTANT: Never use force to remove a terminal from a connector.
6. Inspect the terminal and connector for damage. Repair as necessary. Refer to «Repairing Connector Terminals»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
7. Reform the lock tang (2) and reset terminal in connector body.
8. Close secondary locks and join connector halves.
9. Verify that circuit is complete and working satisfactorily.
10. Perform system check.

J-38125 Terminal Repair Kit. See Special Tools .

Terminal Removal

Follow the steps below in order to repair push to seat connectors.

1. Remove the terminal position assurance (TPA) device, the connector position assurance (CPA) device, and/or the secondary lock.
2. Separate the connector halves (1).
3. Use the proper pick or removal tool (1) in order to release the terminal. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
4. Gently pull the cable and the terminal (2) out of the back of the connector.
5. Re-form the locking device if you are going to reuse the terminal (1).
6. To repair the terminal, refer to «Terminal Repair»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__terminal-repair) .

Terminal Repair

1. Slip the cable seal away from the terminal.
2. Cut the wire as close to the terminal as possible.
3. Slip a new cable seal onto the wire.
4. Strip 5 mm (3/16 in) of insulation from the wire.
5. Crimp a new terminal to the wire.
6. Solder the crimp with rosin core solder.
7. Slide the cable seal toward the terminal.
8. Crimp the cable seal and the insulation.
9. If the connector is outside of the passenger compartment, apply grease to the connector.

Reinstalling Terminal

1. In order to reuse a terminal or lead assembly, refer to «Wiring Repairs»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs) .
2. Ensure that the cable seal is kept on the terminal side of the splice.
3. Insert the lead from the back until it catches.
4. Install the TPA, CPA, and/or the secondary locks.

J-38125 Terminal Repair Kit. See Special Tools .

If the terminal is visibly damaged or is suspected of having a faulty connection, the terminal should be replaced.

Follow the steps below in order to repair pull-to-seat connectors

1. Remove the connector position assurance (CPA) device and/or the secondary lock.
2. Disconnect the connector from the component or separate the connectors for in-line connectors.
3. Remove the terminal position assurance (TPA) device.
4. Insert the proper pick or removal tool into the front of the connector body.
5. Grasp the wire at the back of the connector body and gently push the terminal (1) out the front of the connector body (3).

1. If the wire needed to be cut in order to remove the terminal, gently push a small length of the same size wire through the back of the connector cavity until there is enough wire exposed in order to crimp on a new terminal. If the wire was not cut, cut the existing wire as close to the old terminal as possible.
2. Strip 5 mm (3/16 in) of insulation from the wire.
3. Crimp a new terminal to the wire.
4. Solder the crimp with rosin core solder.

Terminal Installation

1. Align the terminal and pull the wire from the back of the connector in order to seat the terminal.
2. If necessary, cut the new wire to proper length and splice with existing circuit. Refer to «Splicing Copper Wire Using Splice Sleeves»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
3. If the connector is outside of the passenger compartment, apply dielectric grease to the connector.
4. Install the TPA, CPA, and/or the secondary locks.

J-38125 Terminal Repair Kit. See Special Tools .

There are 2 styles of Micro-Pack 100W connectors. These connectors are very similar but use different terminals and have some minor physical differences also.

Scheme 26

The first connector design of the Micro-Pack 100W (1) has a white connector interface that holds the terminals. The second design of the Micro-Pack 100W (2) has a gray interface to hold the terminals. Also, the first design has terminal cavities that are further apart (3 mm centerline) and offset from the other row of terminal cavities in the connector. The second design has terminals cavities that are closer together (2.54 mm centerline) and aligned vertically. One other way to identify the second design is the thin strip of material that runs along the outside of the cavities.

Scheme 27

Follow the steps below in order to remove terminals from Micro-Pack 100W connectors. Some Micro-Pack 100W connector disassembly procedures will vary. Use this procedure as a guide.

1. Disconnect the connector from the component.
2. Locate the nose piece locking tabs that are positioned on the side of the connector nose piece. The connector nose piece acts as a terminal positive assurance (TPA) and may be referred to as such.
3. Use a small flat-blade tool to push in one of the locking tabs while gently pulling on the same side of the nose piece.
4. Repeat the procedure for the other locking tab and remove the nose piece.
5. Remove the wire dress cover. The following is a general procedure for wire dress cover removal. Use this procedure as a guide, some dress cover removal procedures may vary.
6. Use fingers to squeeze the 2 locking legs of the cover.
7. Apply pressure and gently rock the cover until one locking leg is unseated.
8. Continue to apply pressure and rock the cover until the second locking leg is unseated. Repeat procedure for the other side of the dress cover and remove the cover.
9. Use J 38125-12A (GM P/N 12094429) to gently lift the terminal retaining tab while gently pulling the wire out of the back of the connector. Always remember never use force when pulling a terminal out of a connector. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
10. If the terminal is severely bent or damaged, it may be possible on some connectors to push the wire out of the front of the connector instead of pulling it through. This will prevent damage to the internal seals of the connector. Once the terminal is pushed out of the connector, cut the wire as close to the terminal as possible and pull the wire through the connector.

The Micro-Pack 100W connectors have small terminals that are difficult to handle and hold when crimping. In order to aid the technician when crimping these terminals, a new crimping tool was developed. The J 38125-101 (W jaw) crimping tool was developed to crimp Micro-Pack 100W terminals. The J 38125-101 (W jaw) crimping tool has a terminal holding block that will hold the terminal in place while the terminal is being crimped. After the terminal is removed from the connector perform the following procedure in order to repair Micro-Pack 100 terminals.

1. Cut the wire as close to the terminal as possible.
2. Strip 5 mm (3/16 in) of insulation from the wire.
3. Depress the spring loaded locator of the J 38125-101 (W jaw) crimping tool until the terminal holder is completely visible.
4. Insert the terminal into the crimp tool until the core wings are flush with the anvil on the crimp tool. Be sure that the wings are pointed toward the crimp tool former and release the spring locator. The locator will hold the terminal in place. Inspect the alignment of the terminal wings with the crimp tool former. If the terminal wings are wider than the crimp tool former, remove the terminal and bend the terminal wings in slightly.
5. Place stripped wire into terminal.
6. Crimp the new terminal to the wire. If a jam occurs, press the emergency release to open applicator.

After the terminal is crimped to the wire perform the following procedure in order to replace Micro-Pack 100 terminals.

1. Slide the new terminal into the correct cavity at the back of the connector.
2. Push the terminal into the connector until it locks into place. The new terminal should be even with the other terminals. Ensure that the terminal is locked in place by gently pulling on the wire.
3. To assemble the connector, reverse the Terminal Removal Procedure.

J-38125 Terminal Repair Kit. See Special Tools .

Removal Procedure

Follow the steps below in order to remove terminals from Micro 64 connectors.

1. Locate the lever lock on the wire dress cover. While depressing the lock, pull the lever over and past the lock.
2. Disconnect the connector from the component.
3. Locate the dress cover locking tabs at the front of the connector. Using a small flat-blade tool push down on one of the locking tabs and pull the cover up until the dress cover releases. Repeat this procedure for the other locking tab.
4. Once the front 2 locks are unlocked, lift the front of the dress cover and pull it forward.
5. Remove the TPA by inserting a small flat-blade tool into the small slot on the TPA and pushing down until the TPA releases. Gently pry the TPA out of the connector.
6. Insert the J 38125-13A (GM P/N 12031876-1) tool into the round canal between the terminals cavities at the front of the connector. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
7. While holding the removal tool in place, gently pull the wire out of the back of the connector. Always remember never use force when pulling a terminal out of a connector.

Repair Procedure

Follow the steps below in order to repair Micro 64 connector terminals.

The Micro 64 connectors have small terminals that are difficult to handle and hold when crimping. In order to aid the technician when crimping these terminals, a new crimping tool was developed. The J 38125-64 (M jaw) was developed to crimp Micro 64 terminals. The J 38125-64 crimping tool has a terminal holding block that will hold the terminal in place while the terminal is being crimped. The J 38125-64 crimping tool is also designed to crimp both the wire and the insulation at the same time.

After the terminal is removed from the connector perform the following procedure in order to repair Micro 64 terminals.

1. Cut the wire as close to the damaged terminal as possible.
2. Strip 5 mm (3/16 in) of insulation from the wire.
3. Depress the spring loaded locator of the crimping tool until the terminal holder is completely visible.
4. Insert terminal into the appropriate terminal holder until it hits bottom and stops. The correct terminal holder is determined by the wire size. Also ensure that the terminals wings are pointing towards the former on the tool and the release locator.
5. Insert the stripped cable into the terminal. Insulation should be visible on both sides of the terminal insulation wings.
6. Compress the handles until the ratchet automatically releases.
7. Place the terminal into the appropriate cavity and assemble the connector.

J-38125 Terminal Repair Kit. See Special Tools .

1. Locate the connector position assurance (CPA) on the connector body and pull the CPA out. The CPA is on the wire harness side of connector.
2. Disconnect the connector from the component.
3. Use a small flat-bladed tool to gently pry off the dress cover by inserting the tool under the cover opposite the harness side and prying up.
4. Remove the cover.
5. Using a small flat-bladed tool, push on the side of the nose piece retainer while pushing the nose piece forward with your thumb. This will release the terminal position assurance (TPA).
6. Insert the J 38125-12A (GM P/N 12094429) into the corresponding terminal release cavity. The release cavities are the 2 center rows of cavities on one half of the connector.
7. Pressing the J 38125-12A (GM P/N 12094429) tool in the release cavity of the terminal you are removing, gently pull the wire out of the back of the connector. Always remember never use force when pulling a terminal out of a connector. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .

Use the appropriate terminal and crimper in the J-38125 in order to replace the terminal. See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

1. Disconnect the connector from the component.
2. Insert the J 38125-11A (GM P/N 12094430) tool into the cavity on the lower right hand face of the connector until the terminal release tang access panel slides over.
3. Ensure that the terminal release tang access panel is in the correct location to access the terminals.
4. Push the wire side of the terminal that is being removed toward the connector and hold it in position.
5. Insert the J 38125-11A (GM P/N 12094430) into the terminal release tang access slot located behind the access panel of the connector and press down on the terminal while carefully pulling the terminal out of the connector. Always remember never use force when pulling a terminal out of a connector. If the terminal is difficult to remove, repeat the entire procedure.

Use the appropriate terminal and follow the instructions in the J-38125 . See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

1. Disconnect the connector from the component by pressing down on the connector position assurance (CPA).
2. Use a small flat-bladed tool to release the terminal position assurance (TPA) by inserting the tool in the small recess on the side of the connector and pushing up until the TPA releases from the connector body. The TPA should raise just slightly. Do not try to remove the TPA.
3. Repeat the process for the other side of the connector.
4. Ensure that the TPA is in the proper position to remove the terminals.
5. While pushing the terminal forward, insert the J 38125-24 in the release cavity above the terminal you are removing, gently pull the wire out of the back of the connector. Always remember never use force when pulling a terminal out of a connector. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .

Use the appropriate terminal and follow the instructions in the J-38125 in order to replace the terminal. See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

1. Disconnect the connector from the component.
2. Insert a small flat blade tool in the slot below the front loaded terminal position assurance (TPA) and pry up.
3. Remove the TPA by pulling it out of the connector.
4. Push the wire side of the terminal that is being removed toward the connector and hold it in position.
5. Insert the J 38125-553 (GM P/N 15315247) on a slight upward angle into the cavity below the terminal to be removed. Ensure that the pointed on the end of the tool is facing the bottom of the terminal and it stays in contact with the terminal until it stops on the plastic terminal retainer. See the release tool cross reference in the Reference Guide of the J-38125 to ensure that the correct release tool is used. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
6. Gently pry the plastic terminal retainer down and carefully pull the terminal out of the connector. Always remember never use force when pulling a terminal out of a connector. If the terminal is difficult to remove, repeat the entire procedure.

Use the appropriate terminal and follow the instructions in the J-38125 . See Special Tools .

J-38125 Terminal Repair Kit. See Special Tools .

Use the following repair procedures in order to repair the following

1. Push to Seat terminals
2. Pull to Seat terminals

Some terminals do not require all of the steps shown. Skip the steps that do not apply for your terminal repair. The J-38125 contains further information. See Special Tools .

1. Cut off the terminal between the core and the insulation crimp. Minimize any wire loss. For cable seal terminals, remove the seal.
2. Apply the correct cable seal per gage size of the wire, if used. Slide the seal back along the wire in order to enable insulation removal.
3. Remove the insulation.
4. For sealed terminals only, align the seal with the end of the cable insulation.
5. Position the strip in the terminal. For sealed terminals, position the strip and seal in the terminal.
6. Hand crimp the core wings.
7. Hand crimp the insulation wings. For sealed terminals, hand crimp the insulation wings around the seal and the cable.
8. Solder all of the hand crimp terminals excepting Micro-Pack 100 .64 size. Soldering Micro-Pack 100 World terminals may damage the terminal.

Power and Grounding Schematic Icons

Power and Grounding Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury or unnecessary SIR system repairs

Scheme 28

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

Scheme 38

Scheme 39

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

Scheme 62

Scheme 63

J 43244 Relay Puller Pliers. See Special Tools .

1. Remove the electrical center cover.
2. Locate the relay. Refer to «Electrical Center Identification Views»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views) to locate the electrical center where the relay exists.
3. Using the J 43244 (1) position the tool on opposing corners of the relay (2). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__special-tools) .
4. Remove the relay (2) from the electrical center.

Installation Procedure

1. Install the relay (2) in the same position as removed.
2. Install the electrical center cover.

1. Locate the relay. Refer to the «Master Electrical Component List»(/buick/lacrosse/i-2004-2009/remont/electrical-component-locations/#wiring-systems-component-views__master-electrical-component-list) to locate the relay in the vehicle.
2. Remove any fasteners which hold the relay in place.
3. Remove any connector position assurance (CPA) devices or secondary locks.
4. Separate the relay (1) from the wire harness connector (2).

1. Connect the relay (1) to the wire harness connector (2).
2. Install any connector position assurance (CPA) devices or secondary locks.
3. Install the relay using any fasteners or tape that originally held the relay in place.

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Release and reposition the remote positive battery cable stud cover.
3. Remove the nut retaining the positive battery cable lead to the underhood accessory wiring junction block, then reposition the cable lead away from the junction block.
4. Release the coolant recovery tank hose retainer from the junction block.
5. Release the 4 tabs retaining the junction block to the junction block retainer and reposition the junction block.
6. Disconnect the instrument panel (I/P) wiring harness individual connectors from the junction block.
7. Loosen the bolts retaining the engine, I/P and forward lamp wiring harness connectors to the junction block.
8. Disconnect the engine wiring harness connector from the junction block.
9. Disconnect the I/P wiring harness connector from the junction block.
10. Disconnect the forward lamp wiring harness connector from the junction block.
11. If accessory wiring junction block retainer removal is necessary, perform the following: Release the positive battery cable lead retainers from the junction block retainer, then reposition the cable lead away from the retainer. Remove the nut retaining the junction block retainer to the strut tower. Lift the junction block retainer to release the lower tab and remove the retainer from the vehicle.

1. If accessory wiring junction block retainer installation is necessary, perform the following: Position the junction block retainer to the strut tower and insert the lower tab on the retainer to the slot on the tower. Install the junction block retainer to strut tower nut. Tighten: Tighten the underhood accessory wiring junction block retainer to strut tower nut to 3 N.m (27 lb in). Position the positive battery cable lead end through the slot in the junction block retainer, then secure the cable retainers.
2. Connect the forward lamp wiring harness connector to the junction block.
3. Connect the I/P wiring harness connector to the junction block.
4. Connect the engine wiring harness connector to the junction block.
5. Tighten the bolts retaining the engine, I/P and forward lamp wiring harness connectors to the junction block. Tighten: Tighten the wiring harness connectors to underhood accessory wiring junction block retaining bolts to 7 N.m (62 lb in).
6. Connect the I/P wiring harness individual connectors to the junction block.
7. Position the wiring harnesses and the accessory wiring junction block to the junction block retainer, align the 4 retaining tabs and press into place to secure the junction block.
8. Secure the coolant recovery tank hose retainer to the junction block.
9. Install the positive battery cable lead to the stud on the underhood accessory wiring junction block, then install the cable lead retaining nut. Tighten: Tighten the positive battery cable lead to underhood accessory wiring junction block retaining nut to 10 N.m (89 lb in).
10. Install the remote positive battery cable stud cover.
11. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
2. Remove the outer trim cover. Refer to «Instrument Panel (I/P) Outer Trim Cover Replacement»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
3. Disconnect the body wiring harness from the accessory wiring junction block. Pull the harness away from the block for access.
4. Remove the instrument panel (I/P) compartment. Refer to «Compartment Replacement - Instrument Panel (I/P)»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
5. Remove the junction block bolt.
6. Disengage the junction block tabs from the passenger knee bolster. Pull the junction block away from the I/P.
7. Remove the junction block.

1. Seat the bottom junction block tabs and snap the top of the junction block to the passenger knee bolster.
2. Install the junction block bolt. Tighten: Tighten the junction block bolt to 10 N.m (89 lb in).
3. Connect the body wiring harnesses to the junction block. Tighten: Tighten the connector bolt to 2.5 N.m (22 lb in).
4. Install the I/P compartment. Refer to «Compartment Replacement - Instrument Panel (I/P)»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
5. Install the outer trim cover. Refer to «Instrument Panel (I/P) Outer Trim Cover Replacement»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
6. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.

Special Tools

Special Tools Illustration Tool Number/Description J 25070 Heat Gun 500-700 F J 35616 GM-Approved Terminal Test Kit J 35616-200 Test Light - Probe Kit J 36169-A Fused Jumper Wire J 38125 Terminal Repair Kit J 39200 Digital Multimeter J 42598 Vehicle Data Recorder J 43244 Relay Puller Pliers

Scheme 64

Scheme 65

Scheme 66

Scheme 67

See also:
• SIR Caution
• OBD II SYMBOL DESCRIPTION NOTICE
• TEST PROBE NOTICE
• Control Module References
• Data Link Communications Description and Operation
• Electrical Center Identification Views
• Master Electrical Component List
• Battery Negative Cable Disconnect/Connect Procedure (L26)
• FASTENER NOTICE
• Instrument Panel (I/P) Outer Trim Cover Replacement
• Using Connector Test Adapters
• Probing Electrical Connectors
• Troubleshooting with a Digital Multimeter
• Troubleshooting with a Test Lamp
• Measuring Voltage
• Measuring Voltage Drop
• Measuring Frequency
• Testing for Continuity
• Testing for Short to Ground
• Testing for a Short to Voltage
• Testing for Electrical Intermittents
• Circuit Protection - Circuit Breakers
• Circuit Protection - Fusible Links
• Special Tools
• Circuit Testing
• Checking Aftermarket Accessories
• Splicing Copper Wire Using Splice Clips
• Flat Wire Repairs
• Splicing Twisted or Shielded Cable
• Splicing Inline Harness Diodes
• Connector Repairs
• Wiring Repairs
• Identifying Connectors
• Connector Position Assurance Locks
• Terminal Position Assurance Locks
• Terminal Repair