TB 1-2840-248-20-3
(2) Blue cables with size 12-12 scoop proof connectors with an "06" key arrangement such as found on cables
P/N 6044T83P02 and 6044T83P05.
c. Test procedure for yellow/blue harness insulation resistance check with external megohmmeter.
(1) Set up test equipment on suitable work table area. Plug in megohmmeter to port TP1/TP2 on switch box
where positive lead of megohmmeter is inserted into TP1 and negative lead is inserted into TP2. Ground panel to earth
via E1 ground port on panel.
(2) Run fault test prior to testing session per operator's instructions of harness test set.
(3) Locate and remove both the yellow and blue harnesses from the No. 1 and No. 2 engines in accordance
with TM 55-2840-248-23, Chapter 7 and mark appropriately in order to identify upon reinstallation.
(4) Yellow harness check.
Connect the yellow harness ECU connector (W4P1) to the yellow harness test port (J2) on the test box. All
other yellow harness connectors and test box connectors must be disconnected.
(5) Follow instructions for the particular megohmmeter used while adjusting voltage settings, etc.
Set
multiplier dial to proper megohm range. Set test voltage of 500V DC.
CAUTION
Do not apply AC test voltage. Do not set voltage above 500 volts DC. Use caution due to high
voltage present during this type of testing.
(6) Operate test switches S1 through S31 when testing the yellow harness. Place switches S1 through S31
down to the (-) position before start of testing. Flip S1 up to (+) position, operate megohmmeter per manufacturer's
instructions to obtain reading, record reading. Return S1 to (-) position and place S2 to (+) position, operate
megohmmeter again to obtain reading, record reading. Return S2 to (-) position. Continue with this sequence until all 31
switches have been exercised. Pass value is ten (10) megohms or greater..
NOTE
Only one (1) switch shall be in the (+) position during each test, all other switches shall be in
the (-) position.
(7) After completion of exercising switches S1 through S31 for the yellow harness, this portion of the test is
complete. Failure of any of the 31 switch positions is cause for rejection of harness. See paragraph 9 for correction
procedures.
(8) Disconnect the yellow harness from the J2 port of the switch box.
(9) Blue harness check
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