97 trx200

I believe I have a 97 trx200 type 2. I haven’t been able to find a data plate or Vin number and don’t have the title yet so not for sure its a 97. Anyway to the problem.

The front brakes don’t work, I’ve rebuild the master cylinder and bled and bled but still nothing. My main question is I’ve noticed on the parts sites there is a trx200D A, and a trx200D AN. one uses a switch honda part 35340-HR0-305. And one doesn’t. Mine didn’t have one when I got it but there is a screw hole at the bottom of the master cylinder. There was nothing in this hole when i receivedthe bike. Do I need this switch? What would this switch do? What’s the difference between the A and the AN?

Also looks like fluid is now leaking out of the piston on the rebuild master cylinder. Did I put one of the seals on backwards?

Thank you in advance for putting up with my ignorance, my long post and any answers.