For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningDeployment Inside Vehicle - Vehicle Scrapping Procedure
Deploy the inflator modules inside of the vehicle when destroying the vehicle
or when salvaging the vehicle for parts. This includes, but is
not limited to, the following situations:
The vehicle has completed all useful life.
Irreparable damage occurred to the vehicle in a non-deployment ty ...
Power Steering System Description and Operation
The hydraulic power steering pump is a constant displacement vane-type pump
that provides hydraulic pressure and flow for the power
steering gear. The hydraulic power steering pumps are either belt-driven or
direct-drive, cam-driven.
The power steering fluid reservoir holds the power steerin ...
Safety System Check
Now and then, check that the safety belt reminder light, safety belts, buckles,
latch plates, retractors, and anchorages are all working properly.
Look for any other loose or damaged safety belt system parts that might keep
a safety belt system from doing its job. See your dealer to have it rep ...