General Description, Accessory Heaters
Optional accessary heaters are available from the factory in several configurations. Familiarize yourself with the equipment on your specific vehicle, and follow the manufacturer's operating and maintenance instructions.
Warning: Do not operate fuel-operated heaters in an area where flammable vapors, including gasoline or diesel fumes, are present, such as at filling stations and oil depots. Turn off a fuel-operated heater and allow it shut down completely before entering an area where flammable gases or liquids are present. Heaters continue to operate for up to three minutes after being turned off.
Failure to observe these precautions could cause an explosion or fire, resulting in serious property damage, and personal injury or death.
Notice: Always ensure that air inlet and outlet grilles are not restricted. Restriction of any air inlet or outlet ports could result in damage to the auxiliary heater.
Important: To maintain reliable performance, run the accessory heater for at least 15 minutes every month to prevent fuel from degrading.
On vehicles without Optimized Idle, accessory heaters function when the ignition switch is in the OFF position and the cab load disconnect switch (if equipped) is in the ON position.
On vehicles with Optimized Idle, accessory heaters function when the ignition switch is in the ON or ACC position, the cab load disconnect switch (if equipped) is in the ON position, and the parking brake is engaged. The heater may run briefly after the ignition key has been turned to the OFF position.
Important: Wait eight minutes after shutting down an accessory heater before turning the cab load disconnect switch (CLDS) to OFF.
Note: The low voltage disconnect (LVD) control prevents a heater from draining the batteries below starting voltage.