Hummer H2. Manual - part 1264

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.  

z

Turn ON the engine.  

z

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

z

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

  

Fig. 2: Measuring Voltage Drop 
Courtesy of GENERAL MOTORS CORP. 

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 

The following procedure determines the frequency of a signal. 

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2

  

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 

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 

IMPORTANT: Connecting the DMM to the circuit before pressing the Hz button will allow the 

DMM to autorange to an appropriate range.

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

IMPORTANT: Only use the test lamp procedure on low impedance power and ground 

circuits.

NOTE:

Refer to Test Probe Notice in Cautions and Notices.

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Wiring Systems - Hummer H2