Lit. No. 27366, Rev. 01 February 15, 2008
79
TROUBLESHOOTING GUIDE
CAUTION
Circuit board may be damaged
by static electricity. Always
touch ground before handling
PC board.
To Safely Handle PC Board:
Before disassembling control and
touching the PC board, be sure to
remove any static charge from
yourself. Static charge can build up
as a technician works on the control.
Best practice is to work at a properly
grounded work station with a
grounded wrist strap attached to the
technician. In place of proper work
station, the technician should work in
an oil and solvent free area and
touch a good ground each time
before touching the PC board while
servicing the unit.
Handle the PC board by the edges
only.
Do not touch the carbon (black)
areas of the keypad. Your skin oils
will deteriorate the contact area.
CONTROL/CABLE/PLOW MODULE TEST
CONDITION POSSIBLE CAUSE CORRECTIVE ACTION
Snowplow is not connected • Make sure grille plugs between snowplow and truck are properly connected.
Incomplete harness connection(s) or
damaged harness(es)
• With the vehicle switched accessory ON, test the 4-pin connector inside the cab. If pin 1 does not have 12V
and/or if pin 4 does not have ground, use the electrical schematic in this guide to trace the wires from the
connector back to their source. Look for incomplete connections or damaged wires. Complete connections or
repair/replace damaged wires and harnesses as needed.
Single-pin connector on vehicle
lighting harness is not connected.
• Make sure single-pin connector on vehicle lighting harness is properly connected.
Harnesses connected to Isolation
Module incorrectly.
• Using the electrical schematic in this guide, verify that Isolation Module and harnesses are properly
connected.
Control power
light is not ON.
Control fuse is blown. • Replace all blown fuses in under hood electrical harnesses.
• Make sure all plugs (control, between the snowplow and truck, on the snowplow, etc.) are properly connected.
• If all plugs are properly connected, install a properly working control. If problem is corrected, replace PC board
and/or coiled cord in damaged control.
Control power
light is blinking.
Poor connection, Damaged control
or Damaged Plow Module
• If problem is not corrected with properly working control, replace Plow Module.
Harnesses connected to Isolation
Module incorrectly.
• Using the electrical schematic in this guide, verify that Isolation Module and harnesses are properly
connected.
• Replace all blown fuses on truck and snowplow.
Blown fuse or Damaged Plow
Module
• If fuses are all okay, check for 12V at all coils and primary terminal of motor relay. If 12V is missing from any
coil or relay, replace Plow Module. If 12V is present, go to next Possible Cause.
Damaged harness(es) or cable(s)
• Perform a Solenoid Coil Activation Test (SCAT) according to the instructions in this guide. Replace/repair any
damaged harnesses and cables.
• Install a properly working control. If problem is corrected, replace PC board and/or coiled cord in damaged
control.
Control power
light is ON, but
snowplow does
not respond.
Damaged control or Plow Module
• If problem is not corrected with properly working control, replace Plow Module.