Hummer H1 (2006+). Manual - part 351

12-80

Electrical System

_______________________________________________________

2

Remove the wiper switch from the instrument 
panel. Disconnect the wiper switch from the har-
ness.Using a DVOM, measure resistance between 
terminals 2 and 3 of the switch. Is the resistance 
below the specified value?

<.2

1

Connect the 

intermittent

wiper switch to 

the harness.

 Go to step 3.

Replace the 

wiper switch.

3

Turn the ignition switch to the “RUN” position 
and the intermittent wiper switch to “MEDIUM 
DELAY”. Using a DVOM, set to measure volt-
age, back probe the brown wire (CKT 945) at the 
intermittent switch. Voltage should pulse from 12 
volts to 0 volts every 2-7 seconds depending on 
the switch position. Is the voltage in the specified 
range.

+12v pulse

2-7 seconds

Go to step 5.

Go to step 4.

4

Ignition should be in the “RUN” position. Using a 
DVOM, set to measure the voltage, back probe 
the yellow wire (CKT 65) at the intermittent 
wiper switch. Is the specified voltage present?

+12v

Replace the 
intermittent

wiper switch.

Repair the open 

or bad connec-

tion in CKT 65 

between the 

intermittent

wiper switch 

and fuse 13G.

5

Remove the intermittent wiper relay from the fuse 
box. Turn the ignition switch to the “RUN” posi-
tion. Using a DVOM, measure voltage drop 
between the brown wire (CKT 945) and the black 
wire (CKT 59). The voltage should pulse from 12 
volts to 0 volts every 2 to 7 seconds. Is the volt-
age in the specified ranges? 

+12v pulse

2-7 seconds

Go to step 7.

Go to step 6.

6

Using a DVOM, set to measure resistance, mea-
sure resistance to ground at the black wire (CKT 
59) of the fuse box. Is resistance below specifica-
tion?

<.2

1

Repair the open 

or bad connec-

tion, in CKT 

945 between the 

intermittent

wiper switch 

and the intermit-

tent wiper relay.

Repair open or 

bad connection 

in CKT 59 

between the 

intermittent

wiper relay and 

G4.

7

Turn the ignition to the “RUN” position. Use a 
DVOM, to measure voltage drop between the yel-
low wire (CKT 65) and the black wire (CKT 59). 
Is the specified voltage present?

+12v

Go to step 8.

Repair the open 

or bad connec-

tion in CKT 65 

between fuse 

13G and the 

intermittent
wiper relay.

8

With the ignition switch in the “RUN” position 
and the wipers on “LOW”, check the voltage drop 
between the dark blue wire (CKT 28) at the motor 
and the black wire (CKT 59) at the relay. Does the 
voltage switch from 12 volts to 0 volts as the 
wiper completes its cycle?

0v – +12v – 0v

Replace the 
intermittent
wiper relay.

Go to step 9.

 Windshield Wipers Intermittent Speeds Inoperative (Cont’d)  (Figure 12-158)

Step

Action

Value(s)

Yes

No

______________________________________________________

 Electrical System  12-81

9

Gain access to the wiper motor connection. Back 
probe the black wire (CKT 65) with the positive 
lead, and the brown wire (CKT 59) with the nega-
tive lead. With the ignition on is the voltage drop 
in the specified range?

+12v

Replace the 

wiper motor.

Repair the open 

or bad connec-

tion in CKT 65 

between the 

wiper motor and 

fuse 13G

 Windshield Wipers Intermittent Speeds Inoperative (Cont’d)  (Figure 12-158)

Step

Action

Value(s)

Yes

No

12-82

Electrical System

_______________________________________________________

HEATED WINDSHIELD 

The optional heated windshield is capable of defrosting the windshield glass in less than 10 minutes at 0° F. The system is comprised
of a rocker switch with an integrated time delay module  (Figure 12-57), two relays, and two fuses, and two in-glass heating elements.

Figure 12-57:   Rocker Switch/Time Delay Module Location

The rocker switch/time delay module is mounted in the center dash assembly bezel (Figure 12-57).

Removal

1.

Remove the screws and the center dash assembly bezel (Figure 12-57). 

2.

Lift the connector clip and pull the connector from the rocker switch/time delay module. 

3.

Squeeze the clips on the rocker switch/time delay module and remove the switch/module from the bezel.

Installation

1.

Push the rocker switch/time delay module into the bezel opening and snap into the bezel. 

2.

Attach the electrical connector to the rocker switch/time delay module. 

3.

Install the center dash assembly bezel. 

Figure 12-58:   Heating Element Connection Location

Heated Windshield Element Connection 

The heated windshield element connection is located under the windshield center trim at the bottom of the windshield  (Figure 12-58).

TIME DELAY

MODULE

ROCKER

SWITCH

HEATED

WINDSHIELD

HARNESS

CONNECTOR

CENTER

DASH

ASSEMBLY

BEZEL

DRIVER

SIDE

WINDSHIELD

GLASS

PASSENGER SIDE

WINDSHIELD GLASS

FRONT

CONSOLE

HEATING

ELEMENT

JUNCTIONS

______________________________________________________

 Electrical System  12-83

 Left Heated Windshield Inoperative  (Figure 12-157)

Step

Action

Value(s)

Yes

No

1

Gain access to the heated windshield connections. 
With the ignition in the “RUN” position, preform a 
voltage drop test between the yellow wire (CKT 740) 
and the black wire (CKT 59) going to the left hand 
windshield. Turn the heated windshield “ON”. Is the 
specified voltage present?

+12v

Replace the 

heated        

windshield.

Go to step 2.

2

Using a DVOM,, check the resistance to ground 
at the black wire (CKT 59) going to the left side 
windshield. Does the resistance to ground meet 
the specified range?

<.2

1

Go to step 3.

Repair the open 

or bad connection 

in CKT 59 

between the 

windshield and 

G4.

3

Remove the left hand heated windshield relay from 
the exterior fuse box. Check the voltage drop 
between the brown (CKT 580) and the black wire 
(CKT 59). With the ignition in the run position, turn 
the heated windshield switch to “ON”. Is the speci-
fied voltage present?

+12v

Go to step 4.

Repair the open 

or bad connec-

tion in CKT 580 

between the 

heated wind-

shield switch and 

Heated wind-

shield relay (R-

4).

4

With the ignition still in the run position and the 
relay still removed. Preform a voltage drop test 
between the black wire (CKT 59) and the red wire 
(CKT 738). Is the specified voltage present?

+12v

Go to step 5.

Repair the open 

or bad connection 

in CKT 738 

between fuse 2C 

and R-4.

5

With a DVOM,, check the resistance between the 
yellow wire (CKT 740) at the relay and the yel-
low wire (CKT 740) at the windshield. Does the 
resistance meet the specified value?

<.2

1

Replace relay 

R-4.

Repair the open 

or bad connection 

in CKT 740 

between the left 

side heated wind-

shield and R-4.

 Right Heated Windshield Inoperative  (Figure 12-157)

Step

Action

Value(s)

Yes

No

1

Gain access to the heated windshield connections. 
With the ignition in the “RUN” position and the 
heated windshield switch on, preform a voltage drop 
test between the purple wire (CKT 739) and the black 
wire (CKT 59) going to the right hand windshield. 
Turn the heated windshield “ON”. Is the specified 
voltage present?

+12v

Replace the 

heated        

windshield.

Go to step 2.