Hummer H2. Manual — part 1341

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

Probing Electrical Connectors

Backprobe

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.

Test Adapter

Description

J-35616-64

Male .64 Series Connector (lt blue)

J-35616-65

Female .64 Series Connector (lt blue)

J-35616-6

Male Flex MICRO-PACK Series Connector (brown)

J-35616-7

Female Flex MICRO-PACK Series Connector (brown)

J-35616-2A

Male Flex 150 Series Connector (gray)

J-35616-3

Female Flex 150 Series Connector (gray)

J-35616-4A

Male Spade 280 Series Connector (purple)

J-35616-5

Female Spade 280 Series Connector (purple)

J-35616-40

Male Flex 480 Series Connector (dk blue)

J-35616-41

Female Flex 480 Series Connector (dk blue)

J-35616-42

Male Flex 630 Series Connector (red)

J-35616-43

Female Flex 630 Series Connector (red)

J-35616-44

Male 800 Series Connector (yellow)

J-35616-45

Female 800 Series Connector (yellow)

J-35616-8

Male Weather Pack Connector (orange)

J-35616-9

Female Weather Pack Connector (orange)

IMPORTANT:

z

Backprobe connector terminals only when specifically required in
diagnostic procedures.

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Do not backprobe a sealed (Weather Pack(R)) connector, less than a 280
series Metri-Pack connector, a Micro-Pack connector, or a flat wire (dock
and lock) connector.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

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

TROUBLESHOOTING WITH A DIGITAL MULTIMETER

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.

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:

z

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

.

z

Disconnect the harness at both ends of the suspected circuit where it connects either to a component or to
other harnesses.

z

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.

z

Backprobing can be a source of damage to connector terminals. Use care
in order to avoid deforming the terminal, either by forcing the test probe
too far into the cavity or by using too large of a test probe.

z

After backprobing any connector, inspect for terminal damage. If terminal
damage is suspected, test for proper terminal contact.

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

IMPORTANT: Circuits which include any solid state control modules, such as the PCM,

should only be tested with a 10 megohm or higher impedance digital
multimeter such as the J 39200 .

IMPORTANT: Disconnect the power feed from the suspect circuit when measuring resistance

with a DMM. This prevents incorrect readings. DMMs apply such a small
voltage to measure resistance that the presence of voltages can upset a
resistance reading.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

TROUBLESHOOTING WITH A TEST LAMP

Tools Required

J 35616-200 12-Volt Unpowered Test Lamp

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.

To properly operate this tool use the following procedures.

Testing For Voltage

When testing for voltage:

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.

Testing For Ground

When testing for ground:

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.

USING FUSED JUMPER WIRES

Tools Required

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

The J 36169-A includes small clamp connectors that provide adaptation to most connectors without damage.
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. See Special Tools and Equipment

MEASURING VOLTAGE

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

IMPORTANT: A fused jumper may not protect solid state components from being damaged.

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

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:

z

Turn ON the ignition, with the engine OFF.

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Turn ON the engine.

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Turn ON the circuit and/or system with a scan tool in Output Controls.

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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

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

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2