Hummer H1 (2002+). Manual — part 211

______________________________________________________

Electrical System 12-71

®

05745159

Oil Pressure Gauge Inoperative

Step

Action

Value(s)

Yes

No

1

Is gauge maxed out?

Repair open or

bad connection

in CKT31 or

gauge sending.

Go to step 2.

2

Using a DVOM set to measure voltage, check for
voltage at the rear of the oil pressure gauge on the
grey wire(CKT30) connect negative meter lead to
ground on black wire(CKT59). With ignition on,
is voltage present?

12v

Go to step 4.

Go to step 3.

3

Move the negative meter lead to a known good
ground. Is voltage present?

12v

Repair open or

bad connection

in CKT59

between oil

pressure gauge

and G4.

Repair open,

bad connection

or short in

CKT30 between

oil pressure

gauge and fuse

4B.

4

Ignition on, remove the tan wire (CKT 31) from
the oil pressure gauge. Does the gauge max out?

Go to step 5.

Replace the oil

pressure gauge.

5

Reconnect signal wire to gauge. Disconnect sig-
nal wire(CKT31) at sending unit. With ignition on
does gauge max out?

Replace send-

ing unit.

Repair short to

ground in

CKT31.

4-1-00

12-72

Electrical System

_______________________________________________________

®

Fuel Gauge Inoperative

Step

Action

Value(s)

Yes

No

1

Using a DVOM set to measure voltage, check for
voltage at the rear of the fuel gauge on the grey
wire(CKT30) connect negative meter lead to
ground on black wire(CKT59). With ignition on,
is voltage present?

12v

Go to step 3.

Go to step 2.

2

Move the negative meter lead to a known good
ground. IS voltage present?

12v

Repair open or

bad connection

in CKT59

between fuel

gauge and G4.

Repair open,

bad connection

or short in

CKT30 between

fuel gauge and

fuse 4B.

3

With the ignition on, ground the signal lead does
the gauge go to Full?

Full

Go to step 4.

Replace gauge.

4

Disconnect fuel selector valve. Using a jumper
wire, ground the pink wire(CKT29). With the
ignition on does the fuel gauge go to full?

Full

Go to step 5.

Repair open or

bad connection

in CKT29

between fuel

gauge and fuel
selector valve?

5

Determine fuel level in the main tank. Using a
DVOM set to measure resistance, measure resis-
tance to ground on the blue wire(CKT673). Does
resistance value correspond with fuel level in
tank.

Empty=268

Ω

Half=124.4

Ω

Full=19.3

Ω

Go to step 6.

Go to step 7.

6

Determine fuel level in the auxiliary tank. Using a
DVOM set to measure resistance, measure resis-
tance to ground on the yellow wire(CKT675).
Does resistance value correspond with fuel level
in tank.

Empty=268

Ω

Half=124.4

Ω

Full=19.3

Ω

Replace fuel

selector valve.

Go to step 7.

7

Gain access to fuel level sending unit connectors.
Using a DVOM set to measure resistance, check
resistance through the sending unit. Does resis-
tance value correspond with the fuel level in the
tank?

Empty=268

Ω

Half=124.4

Ω

Full=19.3

Ω

Repair open,

bad connection

or short in CKT
673, 675, or 58.

Replace send-

ing unit.

4-1-00

______________________________________________________

Electrical System 12-73

®

05745159

Engine Temperature Gauge Inoperative

Step

Action

Value(s)

Yes

No

1

Is gauge maxed out with ignition on?

Repair short to

ground in CKT

39 or faulty

sending unit.

Go to step 2.

2

Using a DVOM set to measure voltage, check for
voltage at the rear of the oil pressure gauge on the
grey wire(CKT39) connect negative meter lead to
ground on black wire(CKT59). With ignition on,
is voltage present?

12v

Go to step 4.

Go to step 3.

3

Move the negative meter lead to a known good
ground. Is voltage present?

12v

Repair open or

bad connection

in CKT59

between oil

pressure gauge

and G4.

Repair open,

bad connection

or short in

CKT30 between

oil pressure

gauge and fuse

4B.

4

With the ignition on, momentarily ground the
dark green wire(CKT30) at the rear of the gauge.
Does the gauge go to maximum?

Go to step 5.

Replace the

temperature

gauge.

5

With the ignition on, momentarily ground the sig-
nal wire(CKT39) at the sending unit. Does the
gauge go to maximum?

Replace the

sending unit.

Repair open, or

bad connection

in CKT39

between gauge

and sending

unit.

4-1-00

12-74

Electrical System

_______________________________________________________

®

Figure 2-93: Gauges Schematic

FUSE
4B
5 AMP
INTERIOR
FUSE BOX

TO

DIMMER

SWITCH

TO IGNITION

VOLT

OIL

SPEEDO

TEMP

FUEL

G

I

L

I

G L

S

G L S

I

I

G L

S

I

G L

S

59 BK

30 GY

17 PP

G4

C3-N6

C3-N7

C3-L7

C1-30

C5-C10

G1

O I L

P R E S S U R E

S E N D E R

TO

IGN

SWITCH

31 TN

353 YL

C3-P9

C1-I8

39 DG

C3-P8

C1-36

C5-A1

29 PK

C3-P7

C1-35

C2-35

C26-B

ENGINE

TEMPERATURE

SENSOR

GAUGE

OUTPUT

FUEL

SELECTOR

VALVE

DIGITAL

RATIO

ADAPTER

(DRA)

SPEEDO

SIGNAL

SPEED SIGNAL

ENGINE

GROUND IGN+

679 LG

676 PP

570 BK

239 PK

8

9

9-S12-059.3

TO VEHICLE

SPEED SENSOR (VSS)

G2

C26-C

675 YL

A

AUX TANK
FUEL LEVEL
SENDING UNIT

MAIN TANK

FUEL LEVEL

SENDING UNIT

673 DB

58 BK

C26-A

B

C38-B

G1

G1

FUSE
3A
20 AMP
EXTERIOR
FUSE BOX

I S

TACHOMETER

G L

644 YL

C3-K9

C1-49

C5-B9

349 YL

TO CTIS
HARNESS

CRANKSHAFT

POSITION

SENSOR

TO PCM

349 YL

12

7

10

4-1-00