REPAIR STEPS
SOLUTION
DIAGRAMS
PROBLEM
MI91.2234
02JUL98
Part 3
REFER TO MP85.5043
REFER TO MP85.5043
REFER TO MP85.5046
WHITE GROUND
BROWN ACC
5 AMP
10 AMP
10 AMP
5 AMP
ACC FUSE
5 AMP
10 AMP
10 AMP
YELLOW IGN
(WHEN APPLICABLE)
After pushing the
"I" button one time:
a. The red indicator
light above the "I"
button does not
come on.
Check power to the control box on the brown or yellow wire in the 3
pin UML. Check the white wire in the 3 pin UML for a proper ground.
Check the 5 amp fuse in the 7" control box. If this is ok, the 7" con-
trol box, the touch panel, or the modular cable is the problem.
b. More than two
yellow lights are lit
or opposite yellow
lights are lit.
Unplug the sensing unit MTA connector from the 7" control box. If the
lights DO NOT go out, replace the control box. If the lights go out,
connect a 12 volt test light to ground. Touch each of the four pins for
WHITE GND
YELLOW LS
BLACK FRONT
GREEN RD
RED REAR
SENSOR
c. The "NOT IN
PARK/BRAKE"
light is lit.
Check that the transmission is in the proper park position and that the
park brake is set. Some park brakes automatically set when the trans-
mission is placed in park. Trace the blue wire in the 6 pin UML con-
nector to its source. Check for the proper position of the diode arrange-
ment. Check the brake switch for proper function.
NOTE: Most coaches complete a ground signal through the brake
switch, but some do have +12 signal. Make sure the proper box is
being used. Use a jumper wire to apply the proper signal to the blue
wire. If the "NOT IN PARK/BRAKE" light does not go out, replace the
control box.
REFER TO MP85.5043
10 AMP
5 AMP
5 AMP
5 AMP
10 AMP
10 AMP
10 AMP
BLUE HAND/AUTO PARK SWITCH
d. The pump comes
on at this time.
If possible, release the park brake. If the pump continues to run re-
place Relay B. Otherwise, check Terminal 5 with a 12 volt test light
connected to ground. If +12 volts is present, the problem is with the
control box. If +12 is NOT present, replace Relay B.
REFER TO MP85.5060
Part 4
After pushing the
"I" button a second
time:
a. The red indica-
tor light above the
"I" button does
not flash.
Push the "OFF" button, then the "I" button twice. If the light still does
not flash, replace the control box.
the sensing unit. Only on light per pin should come on. Connect the
test light to +12 and check the ground pin. If the sensing unit pins in
the control box function correctly, replace the sensing unit. If not, re-
place the control box.
(PUMP RELAY)
RELAY B
GRAY
TO BRAKE LIGHT
ON DASH (LABELED)
TO PARK BRAKE
SWITCH (LABELED)
