What does the hicas light mean on your r33 skyline rear wheel drive?

It means there is a problem with your HICAS. HICAS steers your rear wheels at high speed moving not more than 2 degrees + or -.

The light has come on indicating that there is a problem.

This is where is gets fuzzy because the problems are hard to trace down.

It could be a fuse, it could be a bad sensor, it could be low Transmission Fluid (even though HICAS is electrical on a r33), it could be your HICAS ECU.

Good luck