I’ve looked for this plane in the Marketplace and I don’t see it. I see the 170-175, 190-195, 300E and EMB-110.
Regardless, the plane you’ve purchased isn’t a default Asobo/Microsoft plane. If the developer of your plane has not implemented the Weather Radar, then it isn’t going to work no matter what Asobo does to improve the WX within the sim.
For instance, I have the EMB-110. The developer included a Bendix / King weather radar unit on the instrument panel. However, the developer has not coded the WX unit to access the WX API in the sim. The developer hasn’t even coded the unit to function, at all. It’s not going to work unless the developer updates the plane to have the unit function.
It is possible that is what you’re experiencing with the aircraft you’re trying to use the weather radar on.