Light Switch

[Rancherchas]

Well, I'm new to the world of military trucks. I just bought a practically new (1990 model) m923a2 and it has been a joy and a curse. It runs fine but no lights, horn, etc. Bought the maintenance cd (don't know how one can do without it) and now have everything working but for the life of me, I can't figure out the strange light switch (it is new). What does the unlock lever do? Also, unless I have done something wrong, the turn signals only work in certain top lever positions. Advice would be welcome-by the way, new to the forum located in OK near the KS border.

Thanks all.

 

[Valence]

Welcome!

Many technical manuals are freely downloadable from the site here for your truck. See the "Technical Manuals" link above.

I believe the truck you have, M923, is what is termed an M939 series, and those TM's are here:
http://www.steelsoldiers.com/showthread.php?79228-TM-s-for-the-939-series-trucks

You'll definitely want/need to start with the "TM9-2320-272-10 Operations manual" to safely operate this truck.
(Don't be overwhelmed by the manual when it talks about other truck configurations other than you own M923A2)

The light switch you're referring to is called the "3-lever light switch" and there are many, many threads about it:
(FYI: the 3-lever is the older style. There are newer fancy push-button switches which, I believe, are drop-in replacements)
http://www.steelsoldiers.com/showthread.php?32101-operation-of-the-3lever-light-switch


Here's also a handy pin-out reference:
http://olive-drab.com/od_mseries_lightswitch.php



In short:
The lock lever must be used to "unlock" the regular operating lights (turn signals, head lights, tail lights, etc). The idea was to make it a deliberate decision to turn on the lights, which should reduce the chance of accidentally turning on the lights during military operations when the trucks should be running in B.O. (Black Out). You know, help avoid visually giving away the truck/convoy's position.