Hummer H1 (2006+). Manual - part 338

12-28

Electrical System

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3.

Remove the holddown bracket.

4.

Remove the one or both the batteries as required.

5.

Clean the battery tray.

6.

Install one or both the batteries in the tray (Figure 12-27).

7.

Install the holddown bracket and the J-hook.

8.

Connect the battery cables.

BATTERY TRAY REPLACEMENT/INSTALLATION

1.

Disconnect and remove the batteries.

2.

Remove the splash shield and the battery tray shield.

3.

Remove the battery tray from the airlift bracket (Figure 12-27).

4.

Install the battery tray on the airlift bracket.

5.

Install the battery tray shield and the splash shields.

6.

Install and connect the batteries.

BATTERY SPLASH SHIELD 

Splash Shield Removal/ Installation

1.

Remove the bolts securing the splash shield to the battery tray (Figure 12-28).

2.

Install the splash shield to the battery tray and secure with the bolts.

Figure 12-28:   Upper Splash Shield Attachment

UPPER

SPLASH SHIELD

BATTERY TRAY

05-P10-005

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 Electrical System  12-29

MAJOR POWER DISTRIBUTION

The following charts and illustrations convey how power is distributed from the vehicle batteries to the fuse/relay centers.

Power is supplied to the fuse boxes from the batteries through fusible links. Each fuse box has internal power busses that direct the
power to the fuses  (Figure 12-29). The busses are indicated on the fuse charts as follows: I = Ignition,  B = Battery,  A = Acces-
sory,  L = Lamps.

The fuse charts contain a listing of the cavities in the fuse box, the corresponding circuits, wire colors and gauges (ga.). Power is
supplied to an individual fuse by the buss indicated in the left buss column. The circuit number (CKT No.) contains two entries
for a fuse: the power supply buss and the outgoing circuit number. The numbers in the cavity column relate to the cavities indi-
cated on the fuse/relay cavity I.D. illustrations.

Using this information, you can determine which cavity of a fuse is the power supply cavity and which other fuses are supplied by
the same buss.

Figure 12-29:   Major Power And Ground Schematic

ALTERNATOR 

Removal

1.

Disconnect the battery negative cable.

2.

Drain the coolant and remove the coolant over flow tank.

3.

Remove the serpentine drivebelt from the alternator pulley.

4.

Remove the P clamp securing the alternator wires.

5.

Loosen the two bolts securing the alternator to the alternator bracket (Figure 12-30).

6.

Pull the alternator away from the engine. Remove the nut and the lockwasher and disconnect the battery wires from the battery
alternator terminal (Figure 12-31).

7.

Unlock and disconnect the field wire (Figure 12-31).

8.

Remove the alternator from the engine.

12-30

Electrical System

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Installation

1.

Connect the battery wires to the alternator. Secure with the lockwasher and the nut. Tighten the nut to 62-80 lb-in (7-9 N•m).

2.

Connect the field wire connector to the alternator.

3.

Move the alternator into alignment with the bracket and install the mounting bolts. Tighten the bolts 18 lb-ft (25 N•m).

4.

Install the serpentine drivebelt on the pulley and adjust the belt.

5.

Connect the battery negative cable.

Figure 12-30:   Alternator Mounting 

Figure 12-31:   Alternator Connections 

ALTERNATOR

BOLTS

MOUNTING

BATTERY

TERMINAL

FIELD WIRES

BATTERY

WIRES

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 Electrical System  12-31

 Alternator Inoperative (No Charge)  (Figure 12-86)

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check - 
Vehicle?

Go to Step 2 

Go to Diagnostic 

System Check - 

Vehicle in Vehicle 

DTC Information

2

Start the engine. 
Does the charge indicator illuminate.

Go to Step 3 

Go to Symptoms - 

Engine Electrical 

3

NOTE: The green POWER lamp of the tester
should remain illuminated while the tester is be-
ing used.

1.

Turn OFF the ignition.

2.

Connect the red lead of the J 41450-B Uni-
versal CS alternator test harness to the alter-
nator output terminal.

3.

Connect the black lead of the J 41450-B to 
the metal alternator housing.

Does the green POWER lamp on the tester illumi-
nate?

Go to Step 6 

Go to Step 4

4

Measure the voltage from the output terminal of 
the alternator to the alternator metal housing.
Does the voltage measure equal to the specified 
value?

12 Volts

Go to Step 14

Go to Step 5 

5

Measure the voltage from the output terminal of 
the alternator to the battery negative terminal.
Does the voltage measure equal to the specified 
value?

12 Volts

Go to Step 12

Go to Step 11

6

1.

Turn OFF completely the load tool before 
connecting or disconnecting a carbon pile 
load tester to the battery. Otherwise, sparking 
at the terminals could cause battery gasses to 
explode.

2.

Connect a carbon pile tester to the vehicle.

NOTE: Ensure that all alternator output circuit
wires pass through the inductive probe.

3.

Connect an inductive ammeter to the output 
circuit of the alternator.

4.

Disconnect the alternator harness connector.

5.

Locate the matching harness connector on 
the J 41450-B , and connect the connector to 
the alternator.

Does the red DIAGNOSTIC lamp on the tester 
illuminate?

Go to Step 7 

Go to Step 13

7

1.

Start the engine and allow it to idle for 30 
seconds.

2.

Increase the engine speed to 2500 RPM.

Does the red DIAGNOSTIC lamp on the tester 
illuminate?

Go to Step 15 

Go to Step 8