Ignition Switch In Run Position (More Than 10 Seconds)

The leveling system is activated when weight is added to or removed from the rear of the vehicle to maintain the rear of the vehicle level at a predetermined rear suspension height. This is known as the vehicle's trim height. Trim height is controlled by the height sensor. Distance of the body to ground will change with tire size and inflation pressure. When load is added to the vehicle, the body is forced downward, causing the height sensors actuating arm to rotate upward (low-out-of-trim), generating two sensor signals to the control module. After a continuous height sensor of approximately 7 to 13 seconds (time delay), the module activates the air compressor (through a relay), sending air to the adjustable rear shock absorbers through the nylon tubing. As the body raises, the height sensor actuator arm continues rotating downward until the pre-set trim height is obtained. The air compressor is turned OFF by the control module. A similar action takes place whenever weight is removed. The body raises causing the sensor actuator arm to rotate downward (high, out-of-trim), generating two sensor signals to the control module. After a continuous high sensor signal of 7 to 13 seconds (time delay), the module opens the vent solenoid. As the body lowers, the sensor actuating arm is rotated upward until its pre-set trim is obtained. The module then closes the vent solenoid which prevents further air from escaping. Air required for raising or lowering the vehicle is distributed from the compressor by one nylon air line which is connected between the compressor dryer and the lefthand air shock absorber, which has a dual port quick connect fitting. A second nylon air line starts here and connects to the righthand air shock absorber. The air lines are color coded to identify which air shock they attach to. Shock-to-shock air lines are color coded, natural. Shock-to-compressor air lines are color coded blue on except station wagon models or yellow on station wagon models.

Fig. 3 Automatic leveling system wiring diagram/connectors (Part 1 of 2). 1985 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 3 Automatic leveling system wiring diagram/connectors (Part 2 of 2). 1985 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 4 Automatic leveling system wiring diagram/connectors (Part 1 of 3). 1986 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 4 Automatic leveling system wiring diagram/connectors (Part 2 of 3). 1986 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 4 Automatic leveling system wiring diagram/connectors (Part 3 of 3). 1986 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 5 Automatic leveling system wiring diagram/connectors (Part 1 of 2). 1987 Crown Victoria, Grand Marquis & Lincoln Town Car:

Fig. 5 Automatic leveling system wiring diagram/connectors (Part 2 of 2). 1987 Crown Victoria, Grand Marquis & Lincoln Town Car:

Referring to Figs. 3, 4 and 5, electrical power to operate the load leveling system is distributed by the main body wiring harness. The wiring harnesses involved, and their function in the leveling system, are as follows:
1. 14401-Provides an extension of the ignition switch circuit 298 (ignition switch in RUN position input to the control module).
2. 14A435-Supplies battery power to system. Directly connects to the air compressor motor, air compressor relay and control module.
3. 12614-Directly connects to the rotary height sensor, compressor motor, relay, vent solenoid, and the control module.
The compressor relay and compressor vent solenoid incorporate internal diodes for electrical noise suppression and are polarity sensitive. Ensure care is taken when servicing these components as not to switch the battery feed (positive) and ground (negative) circuits or serious component and/or system damage will result. After turning the ignition switch to the RUN position, if any upward or downward requests cannot be allowed within 2 minutes (compressor run time out) and 1 minute vent time out, the module controls are suspended. Reset operation occurs by cycling the ignition switch from OFF to RUN positions.