I have a new Giant Defy Advanced SL with the Ridesense sensor. I have tried many times to get this to pair with my edge 500 but just can't get it to connect. This is what I have done so far.

Replaced battery
Confirmed magnet placement and sensor lights are working
Reset edge 500.

Any ideas or tips would be greatly appreciated.

In the 800, you have to tell it what kind of sensor you're trying to pair. Speed, Cadence, or Speed + Cadence. If you have a similar choice, which one did you pick?

I chose the Speed setting as I won't be using the cadence.

You'll need to pick speed and cadence since it's a combo device. It's not about what you want, it's about the device. Try changing the sensor setting and repairing.