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TROUBLSHOOTING
APRIL 2021
32DFR108.C
FR2SS-SERIES SERVICE MANUAL
TABLE 4-1: TROUBLESHOOTING GUIDE
Function
Symptom
Possible Cause
Remedy
Reversed op-
eration
Ramp stows when
STOW/DEPLOY
switch is set to
DEPLOY; ramp de-
ploys when
STOW/DEPLOY
switch is set to
STOW; unit will only
deploy about 10 inch-
es and will only stow
when past the vertical
mark
Hydraulic lines are not
connected correctly
Verify that hydraulic lines to hydraulic pump, flow
control valves and hydraulic actuator are con-
nected correctly. Refer to Figure 3-7 in Chapter
3.
Leads not connected
properly on directional
valve solenoids
Verify that connector J8 (the connector with the
black and red wires) is connected to solenoid S1,
and that connector J9 (the connector with the
white and red wires) is connected to solenoid S2.
Refer to Figure 3-10 in
Chapter 3.
Ramp will stow when
DEPLOY switch is de-
pressed/or deploy
when STOW switch is
depressed; ramp will
operate normally oth-
erwise
Bus harness to ramp
interface connector is
not wired correctly
Verify the red STOW lead on STOW/DEPLOY
switch is connected to bus harness connector pin
B, and the black DEPLOY lead is connected to
pin D. Refer to Figure 3-10 in Chapter 3.
Ramp will
function in
one direction,
but not the
other
Ramp will stow, but
not deploy
Deploy valve not oper-
ating properly
Check for DEPLOY signal at hydraulic pump so-
lenoid S1.
Deploy sensor defec-
tive or out of adjust-
ment
Verify that proximity sensor is energized (LED on
sensor indicates operation) and adjusted for cor-
rect gap. Refer to Chap.2 section B.2.
Hydraulic pump sole-
noid defective
Replace hydraulic pump.
Interlocks
will not dis-
engage
Constant interlock
signal on pin P1-4
(orange wire)
Ramp not fully stowed
Remove possible obstructions and verify that
ramp is fully stowed.
Misadjusted sensor
target or stow sensor
Adjust sensor target and/or stow sensor; refer to
Chap.2 section B.2.
Stow sensor defective
Replace stow sensor.
Electronic controller
defective
Replace controller.
Wrong fluid
sensor out-
put
Fluid level ok.,
Sensor output High
indicating Low level
Gap between sensor
and reservoir
Loosen bracket and adjust sensor position.
Water/Debris between
sensor and reservoir
Blow out Water/Debris from sensor face using
low pressure air.
Fluid sensor defective
Replace sensor.
