Service Bulletin NTR SB 026 96
Magnum Hitch Diagnostic Codes and Service Manual update
Page 20 of 26
TESTING ROCKSHAFT AND POSITION LEVER POTENTIOMETERS
Position potentiometer Use
the CAS 1638 test box
in position 1 with
CAS 1897
adapter harness (black).
Set the DVM to the 2
decimal place range, do not perform test with the
DVM
in the auto ranging mode.
Move
the position lever forward though the range, the voltage should smoothly drop to approximately
1.4 .2
volts
D.C. in the fully lowered position. When moving the position lever rearward toward the transport position the
voltage should smoothly increase back to its original 4.85
.1
volts
D.C.
once the transport position is reached.
Rockshaft potentiometer Use
the CAS - 1638 in position 2 with the CAS 1897 adapter harness (black). Set
the DVM to the 2 decimal place range, do not perform test with the DVM in the auto ranging mode.
View the
DVM
voltage while raising and lowering the hitch.
As
the hitch lowers the voltage should smoothly decrease
from approximately 4.6 to approximately to .9
.1
volts D.C. in the fully lowered position.
Note: To
completely lower the hitch the up/down switch must be double clicked and held in the momentary
position.
Note:
The over all range of the rockshaft pot is slightly reduced from the calibration procedure. this is due to the
hitch control module stopping the hitch movement just before it reaches the mechanical travel limits as it does
during calibration.
BENCH TESTING
STEP 1
ROCKSHAFT & POSITION LEVER POTENTIOMETERS
STEP 3
Connect the multimeter test leads between the cen-
ter (sense) terminal and the opposite outside
terminal. Rotate the potentiometer through its
working range This reading must
also be smooth
and continuous
Connect the multimeter test leads to each outside
terminal of the potentiometer. Set the multimeter to
the 2K ohm
scale.
Measure
the
total
resistance
across the
potentiometer.
the total resistance value
must be 900 to 1100 ohms. If this value cannot be
obtained, the potentiometer must be replaced.
STEP 2
Connect the multimeter test leads to the center
(sense) terminal and one of the outside terminals.
Locate and turn the pot through its full working
range. The multimeter reading must be smooth and
continuous through the full working range.
Summary of Contents for Magnum 7210
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