If that can help, look in the AMM Chapter 34-41-00 page 505, you will find the subtask (34-41-00-720-050) for a functional test of tilt control:
Extract:
Don't forget one thing, IF you have a radar fitted with autotilt, it's normal not to have ground returns (or minimal) on your ND. Your autotilt radar uses E-GPWS to minimize ground clutter.
So make sure, you try it on MAN position before declaring its tilt faulty.
And no ground returns beyond line of sight! Typically 240Nm at FL370 (D in Nm = 1,23 sqr (H in ft) )
What selected range do you have for ground returns with tilt 3°DN?