TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 1/TASK 1
the engine running.
If the fan does not operate, replace the time
delay following the procedures contained in paragraph 4-31, page 4-50
of the TM.
Step 11. Check the hydraulic control valve for damage. Remove the
hydraulic control valve following the procedures contained in
paragraph 8-20, page 8-48 of the TM. Inspect the valve openings for
debris which would interfere with the control valve's operation.
Clean the hydraulic control valve.
If the valve is unserviceable,
replace it and install a new valve following the procedures in
paragraph 8-20, page 8-48 of the TM.
Step 12. With the engine off, attempt to turn the fan by hand. If
the fan can be turned by hand, replace the fan drive following the
procedures contained in paragraph 3-73, page 3-120
of the TM.
At this point in the troubleshooting procedures, if the
cause of the malfunction has still not been determined, notify
Transmission. In the paragraphs that follow, we will cover two
of the malfunctions found in the transmission.
(1) Troubleshooting the Malfunction:
POSITION OTHER THAN "N" (NEUTRAL).
Check the operation of the neutral safety switch.
Disconnect harness leads 14A and 14B from the neutral safety switch.
Using a multimeter, check for continuity in the switch leads, while
moving the shift lever through the operating ranges.
is indicated in any position other than "N" (NEUTRAL), replace the
neutral safety switch following the procedures contained in paragraph
5-5, page 5-12 of the TM.
Check the transmission shift linkage.
transmission shift linkage so that the vehicle starts only in the
The procedures to follow when adjusting the shift linkage
can be found in paragraph 5-8, page 5-18 of the TM.