Manual Air Removal

Turning the ignition switch from the Run to Off position clears all memory which is stored in the control module. Therefore, a test lamp (used during the actual diagnostic procedure) may not immediately indicate a failure when the ignition switch is returned to the Run position.
When charging the battery (battery is discharged when conducting the actual diagnostic procedure), the ignition switch must first be in the Off position or serious damage to the air compressor relay or motor may occur. However, use of a battery charger while performing the diagnostic tests (described further on in this section) is acceptable. Set the battery charger to a rate to maintain, but not damage, the vehicle battery. The following diagnostic test procedures are guides that will lead to the most probable causes of automatic leveling system problems. It is important to accurately identify the problem or condition before selecting and using the appropriate diagnosis procedures and charts described further on. Whenever conducting diagnosis procedures, always cycle the ignition ON then Off, before starting the actual diagnosis or test procedure to ensure vent solenoid and compressor reset ON times.

When compressed air enters the rear load leveling system, its only normal means of escape is through the electrically controlled air vent solenoid. To bleed air from the system manually, place a Schrader type tire valve on the air compressor. Remove the black plastic protective cap and depress the inner valve stem. When air is fully bled from the system, remove the air line from the dryer or air shocks by pushing down on the retainer and pulling the air line outward.