TM 5-3805-291-23-1
ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0013 00
ENGINE FAN CONTROL SOLENOID CIRCUIT TEST
0013 00
N OT E
Use this procedure to troubleshoot any suspectproblems with engine fan control solenoid for
engine cooling fan.
This procedure covers folowing diagnostic codes:
l
a.
291-05 Engine Cooling Fan Solenoid Open Circuit
b.
291-06 Engine Cooling Fan Solenoid Short to Ground
ECM controls speed of engine coolin fan to provide following benefits:
g
a.
Increased productivity.
b.
Reduced noise.
c.
Improved fuel economy.
d.
Reduced overcooling of engine.
ECM monitors engine coolant temperature, inta e manifold air temperature, and hydraulic oil
k
temperature to determine correct speed for engine cooling fan.
ECM controls fan speed by controlling current to engine fan control solenoid. As current to con-
trol solenoid is changed, angle of fan pump's swashplate changes proportionally. This changes
output of hydraulic oil from fan pump to cooling fan.
If ECM detects a system fault, ECM provides minmum current to solenoid. This ensures a maxi-
i
mum fan speed while fault condition exists.
An override is available with ET This allows fan to be manually changed from minimum to max-
.
imum possible rpm.
427-C0657
Inspect electrical connectors and wiring. Refer to Electrical Connector Inspection (WP 0022 00).
1.
a.
Place battery disconnect switch in OFF position (TM 5-3805-291-10).
b.
Perform 10 lb (45 N) pull test on each wire in ECM connectors associated with ECM power supply.
c.
Check J2/P2 ECM connector (socket-head screw) for proper torque of 60 lb-in. (7 Nm).
d.
Check J1/P1 ECM connector (socket-head screw) for proper torque of 55 lb-in. (6 Nm).
e.
Check harness and wiring for abrasion and pinch points from sensors back to ECM.
