M2/M3 BFV: FIRE SUPPRESSION SYST - OD1607 - LESSON 2/TASK 2
The procedure described below is being used as an
The test results described in this
pathway are not the only results possible when
Always follow the directions in the TM for the
actual test results obtained when troubleshooting
on the vehicle.
(1) PFC Elrond knows that a problem is present.
To make sure
that the problem is in the fire suppression system and not in the
driver's instrument panel light system, he turns ON the MASTER POWER
switch and the ENGINE ACCESSORY switch on the driver's instrument
panel. He then presses the PUSH TO TEST switch and checks to see if
the MANUAL light goes ON.
If the MANUAL light does not come ON at
this point, PFC Elrond knows that the problem is in the driver's
instrument panel light system.
He would then proceed to turn the
ENGINE ACCESSORY and MASTER POWER switches OFF and troubleshoot that
The procedures for troubleshooting the driver's instrument
panel light system will not be covered in this subcourse, but can be
found starting on page 3-497 of the TM.
For the purposes of this
subcourse, assume that the MANUAL light comes ON, and that PFC Elrond
must, therefore, continue with troubleshooting the fire suppression
(2) Since the problem is not in the driver's instrument panel
light system, PFC Elrond needs to determine whether the trouble might
be in the connection of 1W10E13 to terminal 3 (figure 31 on the
following page) of the FIRE SUPPRESSION switch. To determine if this
is so, he uses a multimeter to measure the voltage between the FIRE
SUPPRESSION switch terminal 3 and ground.
If the measurement reads
20 or more volts, PFC Elrond knows that he must then check the
connection on terminal 3 to be sure that 1W10E13 is connected. If it
is not connected, he must connect it and verify that the problem has
If it is connected, the problem is being caused by
wiring harness 1W10, which must be replaced.
However, assume that
PFC Elrond measures the voltage between fire suppression switch
terminal 3 and ground and receives a rating of less than 20 volts.
In this case, he must continue troubleshooting.