Hummer H1 (2002+). Manual — part 206

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Electrical System 12-51

®

05745159

IGNITION SWITCH REPLACEMENT

Removal

1.

Remove steering column covers.

2.

Remove multi switch.

3.

Remove screw and interlock cable from ignition switch
(Figure 2-76).

4.

Remove two capscrews and ignition switch from steering
column.

Installation

1.

Apply thread-locking compound to capscrew threads and
install ignition switch on steering column with two cap-
screws.

2.

Install interlock cable on ignition switch with screw.

3.

Install multi switch.

4.

Install steering column covers.

5.

Ensure ignition switch operates properly.

Brake Shift Interlock Cable System Descrip-
tion (Figure 2-76)

The purpose of the brake shift interlock cable is to prevent a
driver from engaging a transmission gear before the brakes are
applied. When the brake pedal is depressed, voltage from the
brake switch de-energizes the interlock solenoid and the cable
relaxes. The transmission shift lever can then be pulled out of
the park position. If electrical power is lost due to a dead bat-
tery or system failure, the solenoid defaults to the open posi-
tion. With the brake/shift interlock solenoid in the open
position the shifter may be moved to any position.

Figure 2-76: Brake Shift Interlock Cable

SOLENOID

Brake Shift Interlock Cable Inoperative

STEP

ACTION

VALUES

YES

NO

1

Gain access to the brake/shift interlock solenoid.
Using a DVOM check for ground on the black
wire (CKT 59). Does the resistance meet the
specifications?

<.2

Ω

Go to step 2.

Repair the open or

bad connection in

CKT 59 between

the interlock sole-

noid and G4.

2

With the ignition switch in the “run” position
check the voltage at the tan wire (CKT 83). Is the
specified voltage present?

12v

Go to step 3.

Repair the open or

bad connection in

CKT 83 between

the interlock cable

and fuse 1C in the

interior fuse box.

3

With the ignition switch in the “run” position and
the brake switch applied check the voltage at the
red wire (CKT 22) on the brake shift interlock
solenoid. Is the specified voltage present?

12v

Replace the

brake shift inter-

lock cable.

Go to step 4.

4

Gain access to the brake switch. With a DVOM
check the voltage at the orange wire (CKT 10). Is
the specified voltage present?

12v

Replace the

brake switch.

Repair the open or

bad connection on

CKT 10 between

the brake switch

and fuse 4D.

3-1-01

12-52

Electrical System

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Figure 2-77: Shift Interlock Cable Schematic

59 BK

FUSE

4D

15 AMP

INTERIOR

FUSE

BOX

INTERLOCK CABLE SOLENOID

83 TN

G4

TO

TURN SIGNAL

SWITCH

BRAKE
SWITCH

TO

BATTERY

22 RD

FUSE

1C

5 AMP

INTERIOR

FUSE

BOX

TO

IGNITION

9-S12-001

INTERIOR FUSE BOX

10 OR

4-1-00

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Electrical System 12-53

®

05745159

CTIS Compressor Inoperative

Step

Action

Value(s)

Yes

No

1

Using a DVOM set to measure voltage, probe the
terminals on the CTIS compressor. With the CTIS
compressor switch set to inflate, and the ignition
on, is voltage present?

12v

Replace the

compressor

Go to step 2.

2

Move the ground lead to a known good ground
and the positive lead still on the compressor, igni-
tion on, compressor switch on inflate. Is voltage
present?

12v

Repair open or

bad connection

in CKT57

between com-

pressor and G2.

Go to step 3.

3

Remove compressor relay from the exterior fuse
box. Using a DVOM set to measure voltage,
Probe cavity 1(CKT46) of the CTIS compressor
relay socket with the positive lead, and cavity
2(CKT59) with the negative lead. Ignition on,
CTIS compressor switch to on, is voltage present?

12v

Go to step 7.

Go to step 4.

4

Using a DVOM set to measure voltage, check
continuity to ground at cavity 2 of the compressor
relay socket. Is resistance below specification?

<.2

Ω

Go to step 5.

Repair open or

bad connection

in CKT59

between com-

pressor relay

and G2.

5

Remove compressor switch from the dash. Using
a DVOM set to measure voltage. Ignition on,
compressor switch set to inflate. Check for volt-
age on white wire(CKT46). Is voltage present?

12v

Repair open or

bad connection

in CKT46

between com-

pressor switch

and relay.

Go to step 6.

6

Using a DVOM set to measure voltage, turn the
ignition on. Check for voltage at both orange
wires(CKT640) at the rear of the compressor
switch. Is voltage present?

12v

Replace the

compressor

switch.

Repair open,

bad connection

or short in

CKT640

between com-

pressor switch

and fuse 1G.

7

Using a DVOM set to measure continuity mea-
sure continuity between cavity 5(CKT437) of the
compressor relay socket and the green
wire(CKT437) at the compressor. Is resistance
below specifications?

<.2

Ω

Go to step 8.

Repair open,

bad connection,

or short in

CKT437

between relay

and compressor.

8

Using a DVOM set to measure voltage, place the
positive lead in cavity 3 (CKT436) of the com-
pressor relay. Place the ground lead in cavity
86(CKT59). Is voltage present?

<.2

Ω

Replace the

compressor

relay.

Repair open,

bad connection

or short in

CKT436

between com-

pressor relay

and Maxi

fuse#6.

4-1-00

12-54

Electrical System

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CTIS Exhaust Valve Inoperative

Step

Action

Value(s)

Yes

No

1

Disconnect exhaust solenoid. Using a DVOM set
to measure voltage, probe the light green
wire(CKT47) with the positive lead, and the black
wire(CKT57) with the negative lead. Ignition on,
move the compressor switch to deflate. Is voltage
present?

12v

Replace exhaust

solenoid.

Go to step 2.

2

Check continuity to ground on the black
wire(CKT57) at the exhaust solenoid. Is resis-
tance below specification?

<.2

Ω

Go to step 3.

Repair open or

bad connection

in CKT57

between exhaust

solenoid and

G2.

3

Remove compressor switch. Using a DVOM set
to measure voltage, check for voltage at both
orange wires (CKT640). With ignition on is volt-
age present?

12v

Go to step 4.

Repair open,

bad connection

or short in

CKT640

between com-

pressor switch

and fuse 1G.

4

Using a DVOM set to measure voltage, check for
voltage at the light green wire(CKT47) with the
ignition on and compressor switch to deflate. Is
voltage present?

12v

Repair open bad

connection or

short in CKT 47

between com-

pressor switch

and exhaust

solenoid.

Replace com-

pressor switch.

4-1-00