Monitor Lamp Service Function

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.

1. Turning the ignition switch from Off to Run position energizes all system controls and suspends height sensor requests for 7-13 seconds, except for the service monitor lamp which is activated immediately, when the ignition switch is turned to Run position.
2. The monitor lamp blinks approximately 1.0 Hz jointly whenever the compressor relay is ON.
3. Monitor lamp is kept on at abnormal system conditions for the following Key ON operations:
a. Disconnected rear height sensor electrical connector or any one detached line.
b. Accumulated ON time of compressor motor relay (110-130 seconds).
c. Continuous ON of vent solenoid for (55-65 seconds). If the rear height lowers to or below trim position, the vent operation is reset and monitor lamp turns off, for both Key-ON and Key-Off operations.
4. When abnormal program run is detected, the control module suspends all controls and the service monitor lamp remains ON.
5. All system functions of the control module, except compressor relay ON, are energized for 29-31 minutes after ignition switch is turned Off.
6. To reset the system, cycle the ignition switch from Off to Run position.