the last time I changed my rear tire I was surprised how much the simple pull-rod from the pedal to the rear brake drum was hanging up.
I think there are two swing arms that hold the brake rod in place, and both needed a liberal dose of White Lithium grease to be free.
Its possible yours is doing something similar and holding the rear brake switch on as well.
There is a wing-nut on the brake drum lever - push the lever forward, unscrew the captive wing nut all the way, and see if your pedal => pull rod => levers and springs are all moving freely.
If not get some white lithium grease from walmart and have at it. WD40 or other thin spray lubes will loosen it up too, but they dont stay in place long - in a month it will be sticking again if you dont use the spray grease.
Then put the wing nut back on and use it to adjust the rear brake free play. It was probably too loose to begin with if you havent adjusted it in a while.
Last edited by KCW; 08-23-2018 at 02:38 PM.