
98 RENR9348-01
Troubleshooting Section
Test Step 3. Test for Control Input Voltage
at the Timer
A. Remove the wire connection from terminal 3
(control) at the air shutoff timer.
B. Turn the battery disconnect switch to the ON
position.
C. Place the emergency stop switch in the STOP
position.
D. Measure the voltage between the wire that has
been removed from terminal 3 (control) at the air
shutoff time
r and the engine ground stud.
The correct voltage is 24 ± 3 VDC.
E. PlacetheemergencystopswitchintheRUN
position.
F. Again, measure the voltage between the wire that
has been removed from terminal 3 (control) at the
air shutoff
timer and the engine ground stud.
The correct voltage is zero volts.
Turn the battery disconnect switch to the OFF
position.
Restore the wiring to the original configuration.
Expected Re
sult:
The voltage is 24 ± 3 VDC with the emergency stop
switch in t
he STOP position and the voltage is zero
voltswiththeemergencystopswitchintheRUN
position.
Results:
•
OK – The vol
tage is correct for the conditions that
are stated above. The circuit for the emergency
stop is supplying the correct voltage to the air
shutoff ti
mer. Proceed to Test Step 4.
•
Not OK – The voltage is not 24 ± 3 VDC with the
emergency
stop switch in the STOP position and/or
the voltage is not zero volts with the emergency
stop switch in the RUN position.
Repair: There is a problem in the circuit that is
used to control the air shutoff timer. Ensure that
the auxil
iary circuit breaker for the emergency stop
switch has not tripped. The problem may be in the
harness or in a connector between the air shutoff
timer an
d the ECM relay or the problem may be in
the circuit for the emergency stop switch. Check
for voltage at the ECM relay. Repair the harness
and/or t
he connectors. Replace parts, if necessary.
If a proble m with the circuit for the emergency
stop switch is s
uspected, refer to the diagnostic
functional test Troubleshooting, “Emergency Stop
Switch Circuit - Test” for information that is related
to testing the
circuit.
STOP.
Test Step 4. Test the Operation of the Air
Shutoff Timer
A. Remove the wi
re connection from terminal 6 (load)
at the air shutoff timer.
B. Turn the batt
ery disconnect switch to the ON
position.
C. Connect a vol
tmeter between terminal 6 (load) of
the air shutoff timer and the engine ground stud.
D. As the emerge
ncy stop switch is activated,
measure the voltage between terminal 6 (load) of
the air shutoff timer and the engine ground stud.
E. Check the voltage in the circuit as you place the
emergency stop switch in the STOP position.
Note: The timer applies a voltage to terminal 6 for
approximately 2.5 seconds. Run the test as many
timesasne
cessary in order to verify that a voltage
is present at this output. The emergency stop switch
must be reset before the test can be run again.
Place the emergency stop switch in the RUN position.
Turn the ba
ttery disconnect switch to the OFF
position.
Restore th
e wiring to the original configuration.
Expected Result:
The voltage is 24 ± 3 VDC for 2.5 seconds after the
emergency stop switch is activated.
Results:
•
OK – The vol
tage is 24 ± 3 VDC for 2.5 seconds.
The timer is operating correctly. Proceed to Test
Step 5.
•
NotOK –Thevoltageisnot24±3VDCfor2.5
seconds.
Repair: There is a problem with the timer.
There may be a problem in the circuit for the
supply vo
ltage to the timer. Perform the following
procedure:
1. Remove t
he wires from terminals 1 (+Battery)
and 2 (−Battery) of the air shutoff relay.