The warning light has come on and on other sites I've seen posts saying it can be caused by low hydraulic fluid. How high should it be?

They also said to use ATF but how can I tell if if that's what is already in?

The power steering is unaffected.

Nissan documentation below. Fresh DEXRON is red in colour.

TT.net information on Power steering problems and solutions:

http://www.twinturbo.net/nissan/300zx/forums/main/view/1109051/Power-steering-problems-and-solutions.html

Edited May 24May 24 by AndrewG