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:

California Proposition 65 WarningDriver or Passenger Seat Head Restraint Guide Replacement
Driver or Passenger Seat Head Restraint Guide Replacement
Callout
Component Name
Preliminary Procedure
Remove the seat head restraint. Refer to Driver or Passenger Seat Head
Restraint Replacement.
1
...
Heater Core Inlet Tube Replacement
Heater Core Inlet Tube Replacement
Callout
Component Name
Preliminary Procedures
Remove the Heater and Air Conditioning Evaporator and Blower Module.
Refer to Heater and Air Conditioning Evaporator and Blower Module Removal
...
Engine Control Module Replacement
Engine Control Module Replacement
Callout
Component Name
Note: If the ECM is to be replaced, the ECM must be RESET
(prepared for removal) prior to removal from the vehicle. Failing to
reset the ECM will result in the ...