  We discuss three promising diagnostic probes of the couplings of a possible
heavy $Z'$ boson at hadron colliders: the forward-backward asymmetry into
leptons, the rare decay $Z' \ra W^{\pm} \ell^{\mp} \nu$, and associated
production $pp \ra Z'W,\; Z'Z$. A general model-independent framework is
proposed for interpreting these and other data. Clean tests of whether a new
$W'$ couples to right-handed currents, of the ratio $g_R/g_L$ of gauge
couplings, and of the non-abelian vertex in left-right symmetric models are
described.
