Special Application Services

• Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000 km/3,000 mi.
• Have underbody flushing service performed once a year.

    See also:

    Customer Assistance Offices (U.S. and Canada)
    GMC encourages customers to call the toll-free number for assistance. However, if a customer wishes to write or e-mail GMC, the letter should be addressed to: United States GMC Customer Assistance ...

    Air Conditioning
    A/C (Air Conditioning): Press to turn the air conditioning on or off. If the fan is turned off or the outside temperature falls below freezing, the air conditioning will not work. When in AUTO, th ...

    Power Outlets
    The accessory power outlets can be used to connect electrical equipment, such as a cell phone or MP3 player. There are four accessory power outlets in the following locations: below the CD slot, ...