You need to check and make sure the air suspension disable switch is not turned off [located in the trunk] if is, turn it back on, see if Ok.
Otherwise you will need to pull codes from air susp system with a scanner to start the diagnostic procedure.
I'll have to assume its a crown vic, grand marquis or town car..Its in the left [driver's side] fender well underneath the air filter box and washer bottle. A Expedition would be the same area on the other side.
If you find this helpful, please accept my answer. Thanks for using Just Answer.
They are located in the BJB [battery junction box. underneath hood fuse box] I can not give you a diagram with out the model and year. It will be a 30 amp green fuse. you can test them with a voltage meter or test light or pull it out and see if burnt/broken.You check your owner's manual for fuse locations.
I already told you where its located under the air box, you won't be able to see it until you remove the air filter box [housing]
Removal and Installation
WARNING: Do not remove an air spring under any circumstances when there is pressure in the air spring. Do not remove any components supporting an air spring without either exhausting the air or providing support for the air spring to prevent vehicle damage or personal injury.
WARNING: Disconnecting an air line that is connected to the air compressor can cause personal injury or damage to components as high pressure air is vented uncontrolled.
WARNING: Before performing maintenance on any air suspension components, disconnect the power to the system by turning off the air suspension switch located on the LH side of the luggage compartment to prevent vehicle damage or personal injury.
NOTE: To correctly re-install the air lines into the compressor drier, a minimum of 3 mm (1/8 in) of visible white air line must be inserted into the fitting.
NOTE: When the battery is disconnected and reconnected, some abnormal drive symptoms may occur while the vehicle relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 mi) or more to relearn the strategy.
NOTE: After installing the air compressor, it is necessary to inflate the air suspension system. For additional information, refer to Ride Height Adjustments in this section.