Hummer H1 (2006+). Manual - part 344

12-52

Electrical System

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LIGHTING SYSTEM DESCRIPTION

Lighting Schematics

See the following Figures for Lighting Schematics on:

Headlight Schematic (Figure 12-39)

Lighting Buss Schematic (Figure 12-39)

Back Up Light Schematic (Figure 12-40)

Brake Light Schematic (Figure 12-43)

Indicator Light Schematic (Figure 12-44)

Key/Headlight Chime Schematic  (Figure 12-44)

Switches  (Figure 12-36)

The light switches on the instrument panel control the interior and exterior lights of the vehicle.

Figure 12-36:   Lighting Switches

Master Lighting Switch

The master lighting switch activates the headlights and the parking lights. It also sends a +12 volt signal to the dimmer switch to
power the interior panel lighting.

Panel Light Dimmer Switch

The panel light dimmer switch brightens or dims the lights in the instrument panel and accessories. The voltage for the dimmer
switch comes from the master lighting switch when the master lighting switch is in the “Park” or “Lights” Positions.

Dome Light Switch

The dome light switch activates the dome light(s), as well as the courtesy lights located at each seat position. The dome light(s) and
courtesy lights will also come on automatically whenever any door is opened. The activation of the dome lights with the door how-
ever does not run through the dome light switch that is controlled by the door switches.

Multifunction Switch

The multifunction switch is located in the steering column. It is two switches housed in one unit. These switches are as follows:

a.

The main switching unit is the turn/hazard switch. This is were the brakes connect to the hazards to override the flasher.

b.

The high beam selector which allows the driver to change the headlights from low beams to high beams.

Instrument Panel Switch Replacement

NOTE: All instrument panel switches are replaced similarly, with the exception of the dimmer control switch. This procedure covers the
main light switch.

MASTER

LIGHTING

SWITCH

PANEL LIGHT

ALL OTHER

MODELS

DIMMER SWITCH 

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 Electrical System  12-53

Removal

1.

Remove the drivers side closeout panel.

2.

Reach up behind the instrument panel, and disconnect the connector from the switch (Figure 12-37).

3.

Push the switch from the switch housing.

Installation

1.

Install the switch in the switch housing  (Figure 12-37).

2.

Plug the connector into the switch.

3.

Install the drivers side closeout panel.

Figure 12-37:   Master Lighting Switch Removal

Instrument Panel Dimmer Control Switch Replacement

Removal 

1.

Remove the drivers side closeout panel.

2.

Reach up behind the instrument panel and un plug the connector from the switch.

3.

Push the switch from the switch housing. 

Figure 12-38:   Dimmer Control Switch Replacement

Installation

1.

Install the switch in the switch housing (Figure 12-38).

2.

Plug the connector into the switch.

3.

Install the drivers side closeout panel.

HOUSING

CONNECTOR

SWITCH

12-54

Electrical System

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Turn/Hazard Switch

The turn/hazard switch is located in the multifunction switch on the steering column  (Figure 12-39).

Figure 12-39:   Multifunction Switch & Control Lever

The turn/hazard switch can be diagnosed with an ohm meter. If a problem is suspected in the turn/hazard switch, disconnect the
harness from the switch and visually inspect the terminals on the back of the switch. If the terminals appear satisfactory, use the
quick test charts to check the continuity between the specified terminals on the switch. If any of the following circuit checks dis-
agrees with the specified results, the switch is defective and will require replacement.

NOTE: Values of 0-0.2

1 is recommended for a closed circuit. Any values of >0.31 may cause irregular operation of the circuit.

Component Quick Test

Hazard Switch Circuit

Terminals

Switch Position

Values

C40-A (385 TN)

and

C40-D (44 LB)

Hazard Applied

Turn Signals Off

Open Circuit

C40-A (385 TN)

and

C39-A (3 LB),

C39-B (9 YL)

Hazard Applied

Turn Signals Off

Closed Circuit

C40-A (385 TN)

and

C40-E (2 LG),

C40-F (5 DG)

Hazard Applied

Turn Signals Off

Closed Circuit

P08-007.2

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 Electrical System  12-55

Figure 12-40:   Turn Switch Circuit

HORN 

Horn Replacement

Removal

1.

Remove the harness connectors and adapters from the horn.

2.

Remove the nut and the horn from the mounting bracket (Figure 12-41).

NOTE: Overtightening horn mounting nut will distort the horn bellows and result in an “off-key” horn tone.

Installation

1.

Secure the horns to the mounting bracket with the nuts.

2.

Plug the harness connectors and the adapters into the horns.

Turn Switch Circuit  (Figure 12-40)

Terminals

Switch Position

Values

C40-D (44 LB)
and
C39-B (9 YL)

Left Turn
Hazards Off

Closed Circuit

C40-D (44LB)
and
C39-A (3 LB)

Left Turn 
Hazards Off

Closed Circuit

C40-D (44 LB)
and
C40-F (5 DG)

Right Turn
Hazards Off

Closed Circuit

C40-D (44 LB)
and
C40-E (2 LG)

Right Turn 
Hazards Off

Closed Circuit

A

B

C

D

E

F

G

A

B

C

D

E

F

MULTIFUNCTION SWITCH