Hummer H1 (2002+). Manual - part 217

______________________________________________________

 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

_______________________________________________________

®

  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