TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 2/TASK 1
Actual Test Procedures. In the paragraphs that follow, we will
cover three of the tests that may be performed on the HMMWV using the
For each of these tests, we will follow a fictitious
individual while they perform the test procedures.
Also, for each
test procedure, we will select an ultimate conclusion and follow only
those test procedure pathways that lead to that conclusion.
(1) No-Go Test 50 (0-1000 PSI Pressure Test).
For this test
procedure, we will follow Staff Sergeant C. L. Roberts as he performs
no-go test number 50. The ultimate conclusion for this test is that
Install Current Probe.
First, SSG Roberts installs the
current probe around the battery positive cable. He points the arrow
on the probe toward the battery.
Do Current Probe Offset.
Next, SSG Roberts ensures that
vehicle power is off.
He then dials 90 into the TEST SELECT
This test checks the charging system maximum output
current for 0-1500 Amps dc.
He presses and holds the TEST button
until the prompting message CAL appears on the display.
releases the TEST button and waits for the offset value to appear on
the display. The offset value should be between the limits -225 to
The display indicates well within this range; therefore, SSG
Roberts will proceed to the next step.
Step 3. Check Charging System Max Output Current. At this point in
the test procedures, SSG Roberts dials 03 into the TEST SELECT
switches and presses the TEST button. He then dials 10 into the TEST
SELECT switches and again presses the TEST button. He then dials 90
into the TEST SELECT switches and once again presses the TEST button.
Now he starts the vehicle engine and turns on the lights and
After the lights and accessories have been turned on,
SSG Roberts sets the engine speed to 1000 rpm. The alternator output
current for the M998 (which is the type vehicle we are testing)
should be 50 Amps. Upon examining the VTM display, SSG Roberts finds
that the output current is low (24 Amps).
He is then directed to
shut off the engine and to remove the