ELECTRICAL
10.11
FAN MOTOR CURRENT DRAW
Connect ammeter leads
between exposed
Orange/Black terminals at
fan connection.
Connect only the Red/White
terminals at fan connection.
Ammeter
A current draw test will provide a good indication of fan
motor condition. A worn or damaged fan motor will
draw more current, which causes a reduction in blade
speed and reduced cooling.
1.
Turn key to off.
2.
Disconnect the thermistor.
3.
Reconnect fan motor connector to place a DC
ammeter in series as shown in the Illustration.
4.
Be sure fan blade is free to rotate.
5.
Turn ignition key and engine stop switch to “ON”
position. Read the current draw on ammeter with
fan running.
6.
If the fan motor draws more than 7.5 Amps,
replace the motor.
Fan Motor Current Draw:
Less Than 7.5 Amps
OIL COOLER FAN CONTROL
TEST
Oil Cooler Fan Notes
G
Thermistor resistance decreases with
temperature increase
G
Both fan and hot indicator should be on
with the thermistor unplugged
G
Fan blade should rotate drawing air in
through cooler (blowing on engine)
THERMISTOR
RESISTANCE
VS. TEMPERATURE
Oil
Temperature
Resistance
±
20%
Fan
ON/OFF
Hot Light
ON/OFF
77
°
F
(25
°
C)
100K
Ω
Fan
OFF
OFF
240
°
F
(116
°
C)
3.5K
Ω
Fan
OFF
OFF
260
°
F
(127
°
C)
2.5K
Ω
Fan ON
OFF
290
°
F
(143
°
C)
1.6K
Ω
Fan ON
Hot Indi-
cator ON
Battery Voltage
Oil Cooler Fan Circuit
’HOT’ indication and fan ’ON’ with resistor
leads disconnected from module and key on
Power
Control
Module
Indicator
THERMISTOR
BLK/YEL
BLK/YEL
YEL/BLK
R/W
BLU/W
OR/BLK
YEL/BLK
RED/W
RED/W
BRN
Thermistor / Fan Control Test
G
Turn key switch to ON and engine stop
switch to RUN. Do not start engine.
G
Test voltage on R/W wire at vehicle control
module. R/W wire should have 12--14
Volts DC (battery voltage)
G
Disconnect thermistor leads from the main
harness (Black/Yellow wires) - Fan and
Hot
indicator
ON?
(If
not,
test
speedometer, fan motor and circuit)
G
Test the resistance of the thermistor (refer
to temperature/resistance table).
Replace thermistor if out of specified range.
See the wiring diagram or chart for
thermistor resistance values at various oil
temperatures.
The resistance of the
thermistor is approximately100k
Ω
at 77
°
F.
G
Replace vehicle control module and test
system if all else appears okay.
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Summary of Contents for 2009 Trail Blazer 330
Page 94: ...ENGINE 3 48 NOTES P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 110: ...FUEL SYSTEM CARBURETION 4 16 NOTES P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 124: ...BODY STEERING SUSPENSION 5 14 NOTES P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 196: ...ELECTRICAL 10 4 REVERSE LIMIT SYSTEM P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 226: ...ELECTRICAL 10 34 NOTES P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 227: ...ELECTRICAL WIRING DIAGRAM 2009 TRAIL BOSS P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 228: ...ELECTRICAL WIRING DIAGRAM 2009 TRAIL BOSS P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 229: ...ELECTRICAL WIRING DIAGRAM 2009 TRAIL BLAZER P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...
Page 230: ...ELECTRICAL WIRING DIAGRAM 2009 TRAIL BLAZER P a r t S h a r k c o m 8 7 7 9 9 9 5 6 8 6 ...