Individual Solenoid Coil Test - Western HTS Mechanic's Manual

TROUBLESHOOTING GUIDE
SOLENOID COIL ACTIVATION TEST (SCAT)
Off -Truck Testing
1. Remove the hydraulic unit
covers.
2. Unplug the snowplow connectors
from ports A and B of the plow
module.
Plow Module (on hydraulic unit)
LED
29290-2
Diagnostic
Harness
4-Position
Control
Connector
3. Connect the diagnostic harness
connectors A and B to the
matching ports on the plow
module (A to A and B to B).
Lit. No. 41467, Rev. 01
4. Plug the connectors removed
from the plow module into the
matching connectors on the
diagnostic harness (A to A and
B to B).
5. Connect the snowplow control
into the 4-position control
connector on the diagnostic
harness.
6. Connect a 12V power source
to the snowplow battery cable
(POSITIVE [+] 12V to the red
wire and NEGATIVE [–] to the
Plug black wire). Turn ON the power
source.
7. Turn the snowplow control ON
and perform a Solenoid Coil
Activation Test (SCAT). See
the following chart for solenoid
numbers and functions. See
the beginning of this section for
instructions on performing a
SCAT.
NOTE: The green LED on the
diagnostic harness will illuminate
when the motor relay function is
activated. This light only tests the
plow module's motor relay output.
Refer to Motor and Motor Relay
Test section for instructions on
properly testing a motor relay.
Solenoid Coil Activation
Test (SCAT) Chart
Control Component(s)
Function Activated
Raise S3 Motor Relay
Lower S1
Angle Right S2, Motor Relay
Angle Left S2, S3, Motor Relay
8. After completing the SCAT, turn
the snowplow control OFF and
disconnect the power source.
9. Perform any required repairs
and retest as needed. Make sure
to disconnect the power source
before removing the diagnostic
harness.
INDIVIDUAL SOLENOID COIL
TEST
1. Remove both wires from coil
terminals.
2. Attach an ohmmeter across the
coil terminals.
3. A reading that is not
approximately 7 ohm indicates
coil is damaged and must be
replaced.
4. Attach an ohmmeter to one coil
terminal and to the steel washer
at the end of the coil.
5. A reading that is not "open"
indicates that the coil has an
internal short and needs to be
replaced.
6. If both readings are OK
(i.e., approximately 7 ohm across
terminals and "open" between
terminal and washer), then the
coil is good.
NOTE: A good coil will draw
approximately 1.5A.
April 15, 2021
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