City/Hiway

[Andy4639]

Does anybody know what the setting's mean for the under dash AC unit's.

Mine has the setting's...City/Hiway and I'm trying to figure out what they are and what is the difference between them. Surely somebody on here knows what they mean and how to use them.

[roboticjunky]

This is what I found on another site.

Some of the instructions for the user are interesting in light of today’s technology. For instance, all units offered “city” or “hiway” knob positions. We think the “city” position was what we know today as “recirculate,” which cuts off the outside airflow. Regardless of model, the instructions provide some version of “Turn the air control [fan] to the desired setting, then adjust temperature control to coldest “City” setting if maximum cooling is needed.” Sounds just like what we do in today’s cars, non?

After switching to the “hiway” position, operators were reminded that “At prolonged high speeds, the compressor capacity is normally more than is needed and ice may form on the evaporator coil. Icing is readily noticed by a marked decrease in air velocity. To overcome this condition, turn the temperature control to the off position. As soon as the coil is clear and normal air delivery is restored, adjust the temperature control to the ‘hiway’ position.”

[Andy4639]

Originally Posted by roboticjunky

This is what I found on another site.

That's what I assumed but how does a under dash unit cut off the outside air coming into the truck when there is nothing hooked up to the truck t do this?
I'm thinking since this unit is a AC/Heater you would turn the knob to let warm water into the evaporator to de-ice it maybe?

[special-K]

Which would I use on the Baltimore Beltway (I-695) or I-95 through Baltimore? Both?