System Tests

Fig. 26 Rear Leveling Diagnostic Test Pin Location:

A test weight of 275-300 lbs. must be added before starting diagnosis tests.

PREPARATION

NOTE: The following system test requires grounding the diagnostic ground terminal with the ignition switch in the ON position. A monitor lamp must be connected between the Test lamp ground terminal, to display the control module status.
1. Remove protective connector cover from diagnostic connector, located behind the right rear quarter trim panel.
2. Insert a wire into diagnostic ground terminal, and ground the other end of wire by connecting it to compressor ground terminal, body ground or control module fastener.

OPERATION

1. The compressor relay output, from the Control Module (CM), will be activated until the vehicle is in the high position. The maximum relay output operation time is 140-160 seconds. If the expected position is not obtained in this time, the CM will cease testing and the monitor lamp output will be activated until the ignition is cycled from Off to On or 1 hour has passed after the ignition switch was turned to the Off position.
2. Proper operation is indicated by monitor lamp flashing. A continuously lighted monitor lamp indicates a failure.
3. Next the exhaust solenoid output will be activated until the vehicle is in the low position. Maximum exhaust solenoid operation time is 110-130 seconds. If the expected position is not obtained within this time, the CM will cease testing and the monitor lamp will be on continuously until the ignition is cycled from Off to On or 1 hour has passed after the ignition switch was turned to the Off position.
4. Proper operation is indicated by flashing monitor lamp. A continuously lighted monitor lamp indicates a failure.
5. The compressor relay output is then activated to return the vehicle to the level position. Maximum operation time of the relay is 140-160 seconds. If the expected position is not obtained within this time, the CM ceases testing and the monitor lamp is continuously lighted until the ignition is cycled from Off to On or 1 hour has passed after the ignition switch was turned to the Off position.
6. When test is successfully completed, the CM will resume normal operation. Throughout testing vehicle load must be maintained, no loads should be added or removed once the test has been started.
7. If any of the tests fail, refer to DIAGNOSIS.

VERIFICATION TEST

To verify system operation test, disconnect test ground wire, then reconnect and perform test again.
Termination Of Test
The test will be terminated if the diagnostic terminal is disconnected from ground, or the ignition switch is turned OFF.
When the test is terminated, the CM will resume normal operation, unless the test was terminated due to detection of a system malfunction.

TERMINATION OF TEST

The test operation is terminated when any of the following takes place:

1. Disconnecting the diagnostic input from the ground circuit.
2. Turning the ignition switch to the OFF position.

When test operation is terminated the CM resumes normal operation due to it detecting a system malfunction.