Hummer H1 (2006+). Manual - part 357

12-104

Electrical System

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 Compass Mirror Display Inoperative  (Figure 12-96)

Step

Action

Value(s)

Yes

No

1

Turn the ignition to the ON position, and heated 
windshields OFF.
Is the compass mirror display operating?

No problem 

found, or inter-

mittent.

Go to step 2.

2

Gain access to C13, with the ignition ON measure 
voltage on the pink wire. Is voltage present?

Approximate

battery voltage

Go to step 4.

Go to step 3.

3

Check for open, or short to ground in CKT 407 
between compass cutout relay and compass mir-
ror, and CKT 400 between compass cutout relay 
and fuse 2C in the interior fuse box.
Are any problems found?

Repair open or 

short to ground 

in CKT 407 and 

CKT 400.

Replace mirror 

cutout relay.

4

Check continuity to ground at C13 on the black 
wire, is resistance to ground below specified?

>.2

1

Replace com-

pass mirror

Go to step 5.

5

Check for open or bad connection on the black 
wire (CKT 59) between compass mirror and G4.
Are any problems found?

Repair open or 

bad connection 

in CKT 59.

No problem 

found, go to 

step 1.

 Compass Mirror Temperature Display Showing OC, SC or Wrong Temp  (Figure 12-96)

Step

Action

Value(s)

Yes

No

1

Does compass mirror display show “OC” or “SC” 
in place of the temperature?

Go to step 3.

Go to step 2.

2

Gain access to C13, measure resistance between 
the brown wire (CKT 767), and ground. With the 
vehicle at room temperature (70°F), does resis-
tance measured match specifications?

Approx.12 K 

1

Replace com-

pass mirror.

Go to step 3.

3

Measuring resistance to ground on the brown 
wire (CKT 767), does meter display open?

OL

Go to step 4.

Repair bad con-

nection at C13.

4

Disconnect temperature sensor from underbody 
harness. Measure resistance between the two pins 
of the sensor. With the vehicle at room tempera-
ture (70°F), is resistance in range specified? 
Higher temperature gives lower resistance read-
ings.

Approx.12 K 

1

Go to step 5.

Replace the 

temperature

sensor.

5

Measure resistance to ground at temperature sen-
sor connector pin A. Is resistance below speci-
fied?

<.2

1

Go to step 6.

Repair open or 

bad connection 

in CKT 58 

between tem-

perature sensor 

and G2.

6

Check for open, bad connection, or short to 
ground on the brown wire (CKT 767)between 
temperature sensor and compass mirror. Are any 
problems found?

Repair open, 

bad connection, 

or short to 

ground in CKT 

767.

Replace the 

compass mirror.

_____________________________________________________

 Electrical System  12-105

POWER SIDE MIRROR WITH HEATER MIRROR (OPTION)

Description

The side mirrors have an option of an internal heater element to aid in defrosting. Heated side mirrors will only be available if the
truck is equipped with a heated windshield.

The power side mirror system components are: two side mirrors with internal vertical and horizontal control motors (and optional
heater elements), the power mirror switch, and the heated windshield switch (optional). 

Power Side Mirror Heater Operation

Circuit Description

The power side mirror heaters operate In conjunction with the heated windshields. The elements receive ground from circuit 59
(BK) and a power signal from circuit 580 (BR). The voltage signal supplied on circuit 580 (BR) is controlled by the heated wind-
shield switch. When the heated windshield switch is activated, voltage runs through circuit 83 (TN) into the switch and activates an
internal timer. This timer closes a pair of contacts which allows voltage to travel from pin B circuit 83 (TN) to pin A circuit 580
(BR). While the contacts are closed internally, voltage will travel on circuit 580 (BR) to the heated side mirrors.

Power Side Mirror Replacement

Removal

1.

Remove the three mounting screws securing the power mirror assembly and the gasket to the mounting plate (Figure 12-70).

2.

Disconnect the power mirror assembly connector from the door jumper harness. 

3.

Inspect the gasket and replace if damaged.

Installation

NOTE: Ensure the door jumper harness is routed through the gasket before connecting the harness to the power mirror assembly.

1.

Connect the power mirror assembly connector to the door jumper harness (Figure 12-70).

NOTE: Wires from the power mirror assembly must be coiled in the mirror housing to ensure clearance to the attachment points.

2.

Align the power side mirror and the gasket with the mounting plate on the door.

3.

Install the three mounting screws

Figure 12-70:   Power Mirror Assembly Removal

POWER MIRROR

ASSEMBLY

MOUNTING

SCREW

CONNECTOR

GASKET

MOUNTING

PLATE

DOOR

JUMPER

HARNESS

12-106

Electrical System

______________________________________________________

 Power Side Mirrors Inoperative

Step

Action

Value(s)

Yes

No

1

Are both mirrors INOP?

Go to step 2.

Go to step 4.

2

Remove the power mirror switch. With a DVOM, 
check the pink wire (CKT 517) for battery voltage. Is 
the specified voltage present?

> 12.6v

Go to step 3.

Repair CKT 517 

between the power 

mirror switch and 

fuse 3H in the interior 

fuse box.

3

With a DVOM, check the resistance to ground on the 
black wire (CKT 59). Does the resistance meet the 
specifications?

< 0.2 

1

Replace the power 

mirror control 

switch.

Repair CKT 59 

between the power 

mirror switch and 

ground G4.

4

Is only the left side power mirror INOP?

Go to step 5.

Go to step 7

5

Remove the left side power mirror. With a DVOM, 
back probe the orange wire (CKT 942) at C50 with the 
positive lead, and the black wire (CKT 59) with the 
negative lead. With the DVOM set to check voltage, 
move the power mirror switch to the left side and then 
up. In both cases the voltage should change from 0v to 
+12v. Does the voltage change?

0v - off

+12v - left

0v - off

+12v - up

Replace the power 

side mirror.

Go to step 6.

6

With a DVOM, check resistance on the orange wire 
(CKT 942) between the power side mirror and the 
power mirror control switch. Does the resistance on 
the circuit meet specifications?

< 0.2 

1

Replace the power 

mirror switch.

Repair CKT 942 

between the power 

side mirror and the 

power mirror switch.

7

Remove the left side power mirror. With a DVOM, 
back probe the orange wire (CKT 944) at C51 with the 
positive lead, and the black wire (CKT 59) with the 
negative lead. With the DVOM, set to check voltage 
move the power mirror switch to the left side and then 
up. In both cases the voltage should change from 0v to 
+12v. Does the voltage change?

0v - off

+12v - left

0v - off

+12v - up

Replace the power 

side mirror.

Go to step 8.

8

With a DVOM, check resistance on the orange wire 
(CKT 944) between the power side mirror and the 
power mirror control switch. Does the resistance on 
the circuit meet specifications?

< 0.2 

1

Replace the power 

mirror switch.

Repair circuit CKT 

944 between the 

power side mirror 

and the power mir-

ror switch.

  Power Side Mirror Heater Inoperative  (Figure 12-132)

Step

Action

Value(s)

Yes No

1

Remove the heated windshield switch from the 
bezel. Turn the ignition switch to the ”Run” posi-
tion. Using a DVOM, check the voltage drop 
between the brown wire (CKT 580) and the black 
wire (CKT 58). Is the specified voltage present?

> 12.6v

Repair CKT 580  

between the heated 

windshield switch 

and the relays.

Go to step 2.

_____________________________________________________

 Electrical System  12-107

CRUISE CONTROL SYSTEMS  (FIGURE 12-71)

WARNING:  Testing of cruise control should only be preformed in areas were traffic is light and the road conditions
are stable.

Figure 12-71:   Cruise Control 

Operation of Cruise Control

1.

Move the cruise control switch to the “ON” position.

2.

Accelerate to the desired speed.

3.

Push in the “SET” button on the end of the turn signal lever and release it at the desired speed. This will set the  vehicle speed.
NOTE: The vehicle speed will decrease while the “SET” button is pushed in.

The cruise control will not operate under 35 MPH.

Accelerating with the Cruise Control On

Vehicle speed can be momentarily increased after the desired speed has been set. By pressing the accelerator pedal the speed will
increase. This action will not interfere with the preset cruising speed. The preset speed will resume after the accelerator pedal is re-
leased.

Resetting the Cruise Control to a Higher Speed

There are two ways to reset the cruise control to a higher speed.

1.

Press the accelerator pedal until the desired speed is reached. Push the “SET” button and release it. Speed should set like nor-
mal.

2.

Move the cruise control switch from “ON” to “R/A”. Hold the switch in place until you reach the desired speed and then hold
the control switch in the “R/A” position for half a second and release. Each time this is done the vehicle speed will increase by
1 MPH.

Turning Off the Cruise Control

There are two ways to turn the cruise control off while driving:

1.

Move the cruise control switch to the “OFF” position.

2

Using a DVOM, measure the resistance to ground 
on the black wire (CKT 58) at the heated wind-
shield switch. Does the resistance meet the speci-
fication?

< 0.2 

1

Go to step 3.

Repair CKT 58  

between the heated 

windshield switch 

and G4.

3

Place the ignition in the “Run” position and the 
heated windshield switch in the “On” position. 
Use a DVOM, to check for voltage at both tan 
wires (CKT 83) at the heated windshield switch. 
Is the specified voltage present?

> 12.6v

Replace the heated 
windshield switch.

Repair CKT 83 

between the wind-

shield switch and 

fuse 1C in the inte-

rior fuse box.

  Power Side Mirror Heater Inoperative  (Figure 12-132)

Step

Action

Value(s)

Yes No