  Context. Understanding the connection between outflows, winds, accretion and
disks in the inner protostellar regions is crucial for comprehending star and
planet formation process. Aims. We aim to we explore the inner 300 au of the
protostar IRAS 4A2 as part of the ALMA FAUST Large Program. Methods. We
analysed the kinematical structures of SiO and CH$_3$OH emission with 50 au
resolution. Results. The emission arises from three zones: i) a very compact
and unresolved region ($<$50 au) dominated by the ice sublimation zone, at
$\pm$1.5 km s$^{-1}$ with respect to vsys, traced by methanol; ii) an
intermediate region (between 50 au and 150 au) traced by both SiO and CH$_3$OH,
between 2 and 6 km s$^{-1}$ with respect to vsys, with an inverted velocity
gradient (with respect to the large scale emission), whose origin is not clear;
iii) an extended region ($>$150 au) traced by SiO, above 7 km s$^{-1}$ with
respect to vsys, and dominated by the outflow. In the intermediate region we
estimated a CH$_3$OH/SiO abundance ratio of about 120-400 and a SiO/H$_2$
abundance of 10$^{-8}$. We explored various possibilities to explain the origin
of this region such as, rotating disk/inner envelope, jet on the plane of the
sky/precessing, wide angle disk wind. Conclusions. We propose that CH$_3$OH and
SiO in the inner 100 au probe the base of a wide-angle disk wind. The material
accelerated in the wind crosses the plane of the sky, giving rise to the
observed inverted velocity gradient, and sputtering the grain mantles and cores
releasing CH$_3$OH and SiO. This is the first detection of a disk wind
candidate in SiO, and the second ever in CH$_3$OH.
