Add-on Electrical Equipment
The OnStar system is integrated into the electrical architecture of the vehicle. Do not add any electrical equipment. See Add-On Electrical Equipment. Added electrical equipment may interfere with the operation of the OnStar system and cause it to not operate.
See also:
Compass Zone
Your dealer/retailer will set the correct zone for your
location. If the zone is not set to your location or
you drive out of the area, the variance needs to be
changed to the appropriate zone.
...
Accessories and Modifications
Adding non-dealer accessories or making modifications to the vehicle can affect vehicle performance and safety, including such things as airbags, braking, stability, ride and handling, emissions syste ...
What to Use
WARNING
Adding only plain water or some other liquid to the cooling system can be dangerous. Plain water and other liquids, can boil before the proper coolant mixture will.
The coolant warning sy ...