PS Magazine - TB 43-PS-744
PS, The Preventative Maintenance Monthly
ISSUE 744
NOVEMBER 2014
4
PS 744
NOV 14
5
PS 744
NOV 14
Dear Sir,
Glad to help.
NSN 5961-01-180-5634 is the fuel solenoid diode that burned out in your
HMMWV. When that happens, however, TACOM LCMC recommends replacing it
with a fuel solenoid Fyback diode, NSN 5961-01-593-3791. That diode provides
better electrical protection.
You can tell the two diodes apart by
the protective shrink sleeve on each. The
Fyback diode has a blue sleeve. The old
diode’s sleeve is black.
The old diode is still being used, though.
It should be applied to the horn circuitry
for vehicles with serial number 255269
and above that have the Smart Start System
(S
3
). So both diodes will be added to the
HMMWV parts TMs in a future update.
The main reason for the original diode’s failure is that vehicles are being
improperly slave started. That causes a transient voltage spike that can damage
other electrical components as well as the diode.
±ollowing the improved slave starting procedure released in TACOM
maintenance action message 11-041 can help with this issue. You can ²nd the
message on the TULSA website:
mam/tacom_wn/ma11-041.html
Without bolts seat can flop…
Y
ou’ve got a lot of gear on while in full battle rattle. And that can be pretty uncomfortable
when riding around in your HMMWV. Some Soldiers have figured out that you can recline
the HMMWV commander’s seat by removing bolts, resulting in a more comfortable ride.
But what seems to be a good idea can really be a bad idea in disguise.
Tampering with the HMMWV’s commander’s seat compromises safety. Without all the
bolts, the seat will recline back all right, but it also could flop forward too far if you’re in
an accident or if you have to stop quickly. That could get you hurt!
Safety is more important than comfort. Keep
all
of the seat bolts in place.
Mystery of the Missing Diode
HMMWVs…
Don’t
Compromise
Safety!
New
flyback
diode
has blue
sleeve
Did you
lose
some-
thing?
Nope. I’m hot on the trail
of an NSN for my HMMWV’s
fuel solenoid diode.
well, send
ol’ rover home and put
away the magnifying
glass. I’ve got just
the NSN you need!
HMMWVs…
I thought
I’d be
more
comfortable if I
removed the seat
bolts. but now I
fEel
Worse!
ohh…
…ouch!
uMph!
whoa!
…too far back or…
Keep all seat bolts in place!
…too far forward
Dear Half-Mast,
I’m having a hard time finding the NSN for the fuel solenoid diode for my
HMMWV. The diode connected to wire 54C of the engine wiring harness
burned up. Any assistance you can offer will be greatly appreciated.
CW3 B.S.B.
744 04-05.indd
1-2
9/22/14
4:39 PM
9/30/14
3:41 PM
Click here for a copy of this article to save or email.
Click here for a copy of these articles to save or email.
Back to TopBack to Top
