[TechTalk]

The "tag axle" switch controls the air pressure in the tag axle suspension air bags. Pushing the button toward the "up" side increases air pressure, adding load to the tag axle and taking load (weight) off of the drive axle. It can be used to bring the drive axle load under the limit imposed on the Ohio turnpike. Pushing the button "down" relieves air pressure from the tag axle suspension. This adds weight to the drive axle, increasing traction while driving on mud, snow, or ice. Combined with the driver controlled locking differential, the coach will "walk out" of situations where otherwise it would be stuck and require an expensive tow. If the switch is a momentary type, returning to the center after activation, the air pressure will return to normal when the switch is released. Later model coaches use a positive switch with an audible alarm when activated rather than a momentary switch.