GM Service Manual Online
For 1990-2009 cars only

The power steering fluid level is indicated by marks on a fluid level indicator. The fluid level indicator is located on the fluid reservoir cap. Inspect the fluid level when the engine compartment is cool, about 21°C (70°F). Ensure that the fluid level is at the FULL COLD mark.

When the engine compartment is hot to the touch, about 66°C (150°F), ensure that the fluid level is at the HOT mark.