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Extra plug on old M37 light switch
Posted: Mon Oct 05, 2009 4:13 pm
by 70deuce
Anyone know what the extra smaller canon plug is on the old style light switch??? Thanks
Posted: Mon Oct 05, 2009 5:24 pm
by powerwagontim
I was told that it was for the early turn signals, but it is only hearsay.
I would be interested to know for sure. I have tried to locate a 51 wiring diagram show it, but have not had any luck.
Tim
Posted: Mon Oct 05, 2009 6:34 pm
by cuz
The early Bendix-Scintilla light switch has an extra plug for the trailer harness which originally ran all the way from the switch's small plug to the rear trailer receptacle. This same switch was used on the M38 where it had the same harness setup. This switch was later superceded to a Bendix-Scintilla switch with only the unmachined boss where the small plug had been. As these two plug switches were attrited out the Army dropped the seperate trailer receptacle harnes and went to the molded rubber tap at the rear harness. These switches started phasing out in 1952.
Left is very early 10-34480 (G742 -7729684) Scintilla switch then center is 10-76555-1 (G742-7355600) Scintilla switch and right is first small single plug universal switch by Unicite # 160306 ( G749-7368702).
The G741 ORD 7 lists one more switch G742-7358637. I'm not sure which design this switch is.
And now we know the rest of the story!
Posted: Mon Oct 05, 2009 6:49 pm
by powerwagontim
Great explanation Wes, thanks for setting me straight, and educating us all!
Tim
Posted: Mon Oct 05, 2009 7:15 pm
by 70deuce
Wes, man is that a great explanation. Thanks a bunch. You gave an answer I'm sure lots of people were wondering about. Do you know if that type switch is more valuable than the other types?
Phil C
Posted: Mon Oct 05, 2009 7:30 pm
by cuz
Phil,
I like to believe it is. Both of the Scintilla switches are completely rebuildable and it's a shame that the subsequent switches were all deliberately built as throw aways. They will all interchange and you can even plug in and run the newest one in todays active duty MV's.
Posted: Wed Oct 07, 2009 9:09 am
by knattrass
Our 1954 came with the big single... bought a new current issue one... everything carried over including the 4 mounting screws.
Posted: Sat Oct 10, 2009 9:49 am
by gwalker
The early type switches would be worth more to someone wanting an orignal type switch in there early MV, they are clearly different in appearance, and can be harder to find now. However if you were to use the 1st design you would have to have a 2 piece rear harness for the veh. if you wanted any wires to the trailer socket.
Posted: Sun Oct 11, 2009 7:01 pm
by cuz
Actually you can use the early 2 plug type with a late harness. You simply do not use the small plug receptacle.