  Dirac fermion dark matter models with heavy $Z^{\prime}$ mediators are
subject to stringent constraints from spin-independent direct searches and from
LHC bounds, cornering them to live near the $Z^{\prime}$ resonance. Such
constraints can be relaxed, however, by turning off the vector coupling to
Standard Model fermions, thus weakening direct detection bounds, or by
resorting to light $Z^{\prime}$ masses, below the Z pole, to escape heavy
resonance searches at the LHC. In this work we investigate both cases, as well
as the applicability of our findings to Majorana dark matter. We derive
collider bounds for light $Z^{\prime}$ gauge bosons using the $CL_S$ method,
spin-dependent scattering limits, as well as the spin-independent scattering
rate arising from the evolution of couplings between the energy scale of the
mediator mass and the nuclear energy scale, and indirect detection limits. We
show that such scenarios are still rather constrained by data, and that near
resonance they could accommodate the gamma-ray GeV excess in the Galactic
center.
