MCi Crusader II 1989 Maintenance Manual page 327

Date
1-1-89
Page
9-19
MC-9 MAINTENANCE MANUAL
TROUBLE
CRUISE CONTROL WILL NOT SET
· CAUSE
8. Defective air brake stop lamp switch or associated lines. Per-
form the following tests:
a. Secure coach from rolling by blocking the wheels.
b. Vent all air pressure by opening the drain cocks.
c. Turn ignition or master control switch to ON and observe the
brake lights. If they are lighted, replace the air brake stop
lamp switch.
d. If brake lights are not lighted; close the drain cocks and build
coach air pressure to 100 psi (690 kPa). With engine operat-
ing, apply and release the service brakes.
e. Vent all air pressure by opening the drain cocks.
f. Check for presence of 24
voe
at both terminals of the brake
stop lamp switch. If voltage is present, check for air pressure
trapped in stop lamp switch air line. If air pressure is present,
determine the cause and repair the air system. If no air
pressure is present replace the stop lamp switch.
9. Defective speed sensor. Perform the following test
a Check for loose or improper mounting of speed sensor. Cor-
rect as required.
b. Jack up the coach drive wheels and block the front wheels.
Place transmission in neutral and release the air brakes.
c. Disconnect connector number 2. Measure the resistance
between terminal 3 of the connector and coach ground. H
resistance is not between 250 and 3000 ohms, speed sensor
or associated wiring is shorted or open.
d. Ground pin 3 of connector with a jumper wire. Disconnect
connector 5. Measure tt,e resistance between pin 1 and·
coach ground, and between socket 2 and ground. If the
resistance is greater than 10 ohms in either test replace the
wiring between connectors 2 and 5.
e. Set ohmmeter on lowest DC voltage scale and connect the
leads to pin 1 and socket 2 of'the speed sensor side of
connector 5. Rotate the coach drive wheels and observe the
ohmmeter indication. If the meter needle is not deflected from
one side of O to the other during wheel rotation, the speed
sensor is defective.
10. (Standard Transmission Coach) Clutch pedal travel insuffi-
cient. clutch switch misadjusted or defective. or associated
wiring faulty.
a. Turrt cruise control system power on. Check if clutch pedal
is fully released and in firm contact with clutch switch.
b. With clutch out (released). check for 24 VDC at both termi-
nals of clutch switch. If voltage is present at both terminals,
proceed to step 5.
c. If voltage is present at only one terminal, depress the switch
manually and check for power at both terminals. If there is
power at both terminals when the switch is manually
depressed, the switch requires adjustment. If not. the switch
is defective.
d. If there is not 24 VDC at either switch terminal, turn the
cruise control system off and measure the resistance
across the terminals of the clutch switch. If resistance is
more than 2 ohms, the switch is defective.
e. Measure the resistance across pins 1 and 2 of connector 2.
If the resistance measures more than 5 ohms, the wiring to
the clutch switch is defective.
..