This is how it works, the data comes in the on a pair of wires which should connect to pin 6 and 7 of the RS485 chip. then the 485 chip has power on pin 8 as I remember and ground on pin 5. Pin 2 and 3 are connected to each other and pin 5(grounded) So then data comes out of the chip to the pic on pin #1. I believe it is pin #17 on the pic. So those should be connected. There is a jumper to disconnect it that allows the wireless to talk direct to the pic without the rs485 getting in the way so to speak (pulling the line). with this in mind hope this helps. As far as the data led ignore it, it is not a 100% setup as we found out some rs485 chips do not operate it correctly. now speaking of it. If the led was backwards or damage it could cause you issue so you might want to disconnect it to test.
RJ