Hummer H2. Manual — part 1265

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

With a DMM

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.

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 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).

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When the DMM displays voltage the short is in the wiring leading to the first connector or switch.

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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

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.

TESTING FOR INTERMITTENT CONDITIONS AND POOR CONNECTIONS

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

Tools Required

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J 35616 GM-Approved Terminal Test Kit

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J-38125 Terminal Repair Kit. See Special Tools and Equipment .

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J 42675 Flat-Wire Probe Adapter. See Special Tools and Equipment .

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

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Wiring broken inside the insulation

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Poor connection between the male and female terminal at a connector.

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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.

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Wire insulation which is rubbed through-This causes an intermittent short as the bare area touches other
wiring or parts of the vehicle.

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Refer to Inducing Intermittent Fault Conditions in order to duplicate the conditions required in order
to verify the complaint.

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Refer to Testing for Electrical Intermittents for test procedures to detect intermittent open, high
resistance, short to ground, and short to voltage conditions.

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Refer to Scan Tool Snapshot Procedure for advanced intermittent diagnosis.

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. See
Special Tools and Equipment .

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 and Equipment .

Follow the procedure below in order to test terminal contact.

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2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

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. Replace the female terminal in question. See Special
Tools and Equipment .

Flat Wire (Dock and Lock) Connectors

or

There are no serviceable parts for flat wire (dock and lock) connectors on the harness side or the component
side.

Follow the procedure below in order to test terminal contact.

1. Remove the component in question.

2. Visually inspect each side of the connector for signs of contamination. Avoid touching either side of the

connector as oil from your skin may be a source of contamination as well.

3. Visually inspect the terminal bearing surfaces of the flat wire circuits for splits, cracks, or other

imperfections that could cause poor terminal contact. Visually inspect the component side connector to
ensure that all of the terminals are uniform and free of damage or deformation.

4. Insert the appropriate adapter from the J 42675 on the flat wire harness connector in order to test the

circuit in question. See Special Tools and Equipment .

INDUCING INTERMITTENT FAULT CONDITIONS

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:

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Wiggling the harness

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Disconnecting a connector and reconnecting

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Stressing the mechanical connection of a connector

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Pulling on the harness or wire in order to identify a separation/break inside the insulation

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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 . 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

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

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

Tools Required

J 25070 Heat Gun. See Special Tools and Equipment .

High Temperature Conditions

If the complaint tends to be heat related, you can simulate the condition using the J 25070 . See Special Tools
and Equipment .

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.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2