Sorry by reference i meant the SOURCE.,,where did you get this text from?
You are mentioning the weather radar not the pWS.
From the
AMM:
Additional to „normal“ weather radar system, the predictive windshear function provides horizontal windshear warning up to a range of 3 nautical miles.
In the 737 aircraft, this an additional, fully automatic mode of the weather radar system and is not controlled by the pilots.
And from the AMM again:
When the airplane is on the ground and either throttle is moved more than 53 degrees, the PWS comes on automatically.
But in this case I can refer to Brady's "The B737 Technical Guide".
I trust anybody discussing technical matters about the B737 series has this one in his library.
I dont.