Extra plug on old M37 light switch

[70deuce]

Need some help. What is the second smaller canon plug for on these older style light switch??? Thanks

 

[Capt.Marion]

Part of me wants to say turn signals, but I'm honestly not sure.

 

[NDT]

Not turn signals. I think that early 50's armor used that plug.

 

[rumplecat]

Could it be an IR control. I don't remember how we switched on our IR lights in the M60s?
James

 

[zak]

I believe that its the trailer hookup.

 

[diseased]

I know in the TM the early M-38 harnesses had a separate main and trailer harness.

 

[EZFEED]

Second for the trailer, was working on a buddys 37 and thats where I found the short for his plug out back.