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Crusader
MC-8
MAINTENANCE
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MANUAL
ELECTRONIC SPEEDOMETER TROUBLESHOOTING (CONT'D)
SYMPTOMS
POSSIBLE CAUSE
SOLUTION
F. Needle sticks at one
F.
spot.
1)
Jumps both going up
1)
Bad Head.
and down the scale.
ELECTRIC SPEEDOMETER
WITH ODOMETER
(OPTIONAL)
DESCRIPTION
An electric speedometer with odometer may be in-
stalled on the instrument panel to the left of the
driver and is controlled from a permanent sender
from the transmission.
MAINTENANCE
--The eleetric-speed-ometer-is-asealed-unit and can"
not be repaired or rebuilt in the field, but must be
returned to factory for repair or replacement.
SPEEDOMETER CHECK WITH LEFT
FRONT WHEEL TAKE OFF
DESCRIPTION
A calibrator is available from Motor Coach Industries,
Service Parts Division for checking speedometer readings
on Crusader coaches with the take-off from the left front
wheel.
The calibrator has a light emitting diode (LED) on face
plate. The light flashes at the frequency when calibrating
the speedometer. This will allow the operator to know that
the calibrator is working in the event the speedometer
under test is bad.
The following procedure applies for checking speed-
ometers on bench before installing on coach.
Connect the lead wires of the "pill box" from the
speedometer kit to a 24 volt system. Green and white
ground and red is power supply. Allow approximately a
10
minute warm-up period for the pill box components.
F.
1)
Replace.
I. Disconnect the pick up cable from the instrument or
pill box cable if connected.
2. Connect the calibrator cable to the pill box cable.
NOTE: Make sure there is a 24 volt power supply to the
pill box lead wires. CAUTION: Not the cables.
3. Plug the calibrator power c~rd into a wall socket,
making sure the power supply 1s 60 Hz I
15
V A.C.
4. Place the swtich of the calibrator with the above con-
nected speedometer kit in the "speedometer" positio!1
on the calibrator. CAUTION: Do not select other posi-
tions for checking speedometers.
5. Should it be necessary to reset the calibration, please
note that when damage is caused by force, it ~oids_ the
warranty. If it is decided to change the calibration,
break the seal on the "pill box" and insert a srn_ll.JL
flathea-d screw-dr1ver(max1mum 3 / 32" width) into hole
and very carefully adjust the setting for spee~ometer
accuracy. NOTE: These speedometers are designed to
be accurate to
;t.
one half(½) the needle width. Speed-
ometers in Crusader coaches are to be calibrated for
480 wheel revolutions per mile at 57.5
MPH.
CHECKING SPEEDOMETER IN COACH
NOTE: The pill box is mounted under the left front
dash panel.
To check units that are installed in coaches, proceed as
follows (Refer to illustration "CHECKING SPEED-
OMETER ON BENCH.")
Disconnect the pill box cable from
t?~
pick up cable,
etc. as in previous Steps I to 4. L~ave w!nng connected as
installed. A 24 volt power supply 1s reqmred to operate the
speedometer assembly. The speedometer should read 57._5
MPH. A tolerance of the width of speedometer needle
!S
allowed. If the above reading is not within or close to this
range, the following procedure is recommended.
I. Remove the pill box and bracket assembly from under
the left hand dash to the left of steering column.
2. Disconnect the pick up cable from the "pill box" or
instrument cable.
3. Connect the calibrator cable to the pill box cable.
NOTE: Make sure the main battery switch is in the
"ON" position.
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