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.

 

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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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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 

 

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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