In April of 2002, TACOM and the Defense Supply Center in Columbus, Ohio began a retrofit program to replace the standard three lever light switch on American M-Series military vehicles with a new design based on electronic push buttons. The new switch was required due to maintenance problems with the old, mechanical switch plus the fact that it had no illumination at night.
Today in WW II: 9 Mar 1945 279 B-29 Superfortress bombers ignite a firestorm in Tokyo, destroying 267,000 buildings, creating 1 million Japanese homeless [Mar 9-10].
Replacing the M-Series 3-Lever Light Switch
The revised M-series light switch pushbutton design, pictured above, is a direct plug-in replacement that can be installed in any existing MV that used the 3-lever unit. The coupling on the back of the push button switch is the same MIL-C-28-51 connector as on the 3-lever switch.
Here is a photo of the new and old switches side by side:
The NSN and description for the push button switch is 5930-01-491-9893, Blackout
Switch. The manufacturer is Advanced Input Devices (CAGE code 59666) P/N 9375-00117.
In some documents the switch is not called "Blackout Switch" but rather
is just "Switch Assembly".
There were reports that early production of the pushbutton switch had problems and those units were not reliable. Get a guarantee from any vendor that you will receive a unit from newer production. By 2005 those problems seemed to be solved.
Download the Pushbutton Light Switch Instruction Sheets
The switch comes packed with two pages of instructions and drawings. Click