I presume it's the weather radar in the nose of each aircraft your referring to?
This would not have not have been switched on in either aircraft. Weather radars are off whenever the aircraft is on the ground as they can be harmful to people in close proximity due to their high power. They switch on automatically when the aircraft has left the ground.
Even if this had been switched on in either aircraft, the other aircraft would not have been visible on it.
The only radar that could have influenced events in this crash is ground radar, which was not installed at the airport.