Underbody Maintenance
Use plain water to flush dirt and debris from the vehicle's underbody.
Your dealer or an underbody car washing system can do this. If not removed, rust and corrosion can develop.
See also:
Cellular and GPS Antennas
Avoid placing items over or near the antenna to prevent blocking cellular and
GPS signal reception. Cellular reception is required for OnStar to send remote signals
to the vehicle. ...
Maintenance Replacement Parts
Replacement parts identified below by name, part number, or specification can
be obtained from your dealer.
...
Manual Lumbar
Manual Lumbar
If equipped, increase or decrease manual lumbar support by turning the knob forward or rearward. ...