Sometimes it's just that flimsy piece of copper that acts like a spring that pushes the switch into place. Take it out and spread it a little and reinstall....
If the switch isn't pushed forward it can also do that..

 

How do I get it apart split the control housing?

 

Use a 4mm shim in between the lever and control housing before you loosen the control housing to open it up to get to the copper spring that keeps the switch snug. Not using the 4mm shim is normally how the switch is damaged in the first place.

The red arrows show where to put the shim. A piece of paper folded on itself or cardboard works.

 

There is a little tit on the switch. Not the dome rubber looking cap it shows in the ebay picture. The switch works, seems like the lever will not fully go back out to its original position. How do you keep the paper or cardboard in there? Doesnt that apply slight brake pressure?

 

Yeah, it did the trick for me.Brake felt fine too.

 

Master cylinder bores are aluminum and so is the piston...sometimes they can get gummy and the light spring doesn't push the plunger all the way out which leaves slack in the lever. If your lever stays depressed the brake light switch will be activated.
That would be an
You should bleed first though...how can you say the brake feels fine when you have slack in the lever? No leaks at the master right? That would be an indication of piston or seal failure.

 

The shim is only used when changing the front brake lever or removing the top control housing cover.
You just pull the lever like you're applying a small amount of brake and slip the shim in between the shoulder on the lever and control housing shown in the picture.

 

I meant brake feel was fine. I kind of got away from using the front brake because of this which isn't the safest thing either.

 

Had the same symptoms. The nub was missing off the switch. Here's my fix:

 

OK, here is what it looks like in there