Hummer H1 (2002+). Manual — part 217

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Electrical System 12-93

®

05745159

Figure 12-99: Heated Windshield Schematic

59 BK

FUSE

2C

30 AMP

EXTERIOR

FUSE

BOX

FUSE

2D

30 AMP

EXTERIOR

FUSE

BOX

FUSE

1C

5 AMP

INTERIOR

FUSE

BOX

HEATED

WINDSHIELD

SWITCH

TO

IGNITION

LEFT WINDSHIELD

RIGHT WINDSHIELD

17 PP

58 BK

83 TN

C6-M7

C1-33

580 BR

R-4

LEFT

WINDSHIELD

RELAY

R-2
RIGHT
WINDSHIELD
RELAY

HEATED

WINDSHIELD

RELAYS

G4

59 BK

740 YL

739 PP

59 BK

G1

G1

TO

BATTERY

TO

BATTERY

G4

C1-3

C1-2

TO

DIMMER SWITCH

TO

COMPASS/MIRROR

RELAY

9-S12-009

C6-F3

C6-M8

C6-M6

738 RD

737 OR

TO

HEATED

MIRRORS

HEATED WINDSHIELDS

4-1-00

12-94

Electrical System

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®

Rear Window Defroster Inoperative

Step

Action

Value(s)

Yes

No

1

Gain access to the male side of connector C45 on
the C-pillar intermediate. Turn the key to the
“RUN” position and the heated rear window switch
to the “ON” position. With a DVOM check the volt-
age drop between the pink wire (CKT 689) and the
black wire (CKT 58). Is the specified voltage
present?

12v

Replace the

heated rear win-

dow.

Go to step 2.

2

Check the black wire (CKT 58) for resistance to
ground. Does the resistance meet the specified
value?

<.2

Ω

Go to step 3.

Repair the open

or bad connection

on the CKT 58

between the

heated rear win-

dow and G4.

3

Remove the HVAC control unit from the center
console. Turn the ignition switch to the “RUN”
position and activate the rear window defroster
switch. With a DVOM check the voltage drop, on
connector C46, between terminals D (CKT 689) and
C (CKT 59). Is the specified voltage present?

12v

Repair the open

or bad connection

on CKT 689

between the

HVAC control

and the rear win-

dow defroster.

Go to step 4.

4

Disconnect connector C46 from the back of the
HVAC control unit. With a DVOM check the
resistance to ground on terminal C (CKT 59).
Does the resistance meet the specifications?

<.2

Ω

Go to step 5.

Repair the open

or bad connection

on CKT 59

between the

HVAC control

and G4.

5

With a DVOM check terminal A (CKT 688) for
battery voltage. Is the specified voltage present?

12v

Go to step 6.

Repair the open

or bad connection

on CKT 688

between the

HVAC control

and fuse 4M.

6

Turn the ignition switch to the “RUN” position.
With a DVOM check terminal B (CKT 399) for
battery voltage. Is the specified voltage present?

12v

Replace the

HVAC control

unit.

Repair the open

or bad connection

on CKT 399

between the

HVAC control

and fuse 7C.

4-1-00

______________________________________________________

Electrical System 12-95

®

05745159

Figure 12-100: Rear Window Defroster Schematic

J6

N7

FUSE

7C

30 AMP

INTERIOR

FUSE

BOX

REAR WINDOW
DEFROST SWITCH

REAR WINDOW DEFROSTER

( HMC4 & HMSB )

59 BK

C1-13

G4

58 BK

G4

9-S12-157

C6

C6

G1

A3

TO HVAC

CONTROL

PANEL

399 DG

689 PK

TO

TEMPERATURE

DOOR

CONTROL

C45

B

A

TO

IGNITION

TO
REAR
A/C

FUSE

4M

30 AMP

EXTERIOR

FUSE

BOX

TO

BATTERY

688 RD

688 RD

C46

C46

B

D

C

A

4-1-00

12-96

Electrical System

_______________________________________________________

®

Power Windows Inoperative, All Windows

Step

Action

Value(s)

Yes

No

1

Remove relay R4 from the interior fuse box. With
a DVOM check cavity G7 for resistance to
ground. Does the resistance meet the specified
value?

<.2

Ω

Go to step 2.

Repair the open

or bad connection

in CKT 59

between relay R4

and Ground G4.

2

With a DVOM check the voltage at cavity F7. Is
the specified voltage present?

12v

Go to step 3.

Repair the open

or bad connection

in CKT 175

between R4 and

fuse 5M in the

exterior fuse box.

3

Turn the ignition switch to the “Run” position.
With a DVOM check the voltage at cavity F5. Is
the specified voltage present?

12v

Go to step 4.

Repair the open

or bad connection

in CKT 296

between R4 and

fuse 2G in the

interior fuse box.

4

Remove the drivers door window switch and harness
from the bezel. Disconnect the power window switch
from the harness. With a DVOM check the resistance
between cavity 3 on the drivers power window switch
harness and cavity G5 of the interior fuse box. Does
the resistance meet the specification?

<.2

Ω

Replace relay R4

in the interior

fuse box.

Repair the open

or bad connection

in circuit 171

between the

drivers window

switch and R4.

4-1-00