My 03 navigator suddenly lost all suspension could it be a short or do I have to replace the whole suspension

The air suspension shut-off switch on a Lincoln Town Car, located on the left side of the trunk.

https://www.motor.com/2023/03/diagnosing-and-repairing-ford-air-suspensions



https://www.justanswer.com/ford-lincoln/7jr4z-lincoln-navigator-ultimate-electronic-suspension.html

on of the suspension sensors failed or short is wiring

This is a very complicated and expensive system to maintain. I would strongly recommend doing a air suspension conversion on your Navigator and be done with the problem forever.

Lincoln Navigator Air Suspension Conversion 03 06

The air bags are leaking, replace them as a pair.

If the rear suspension is not affected its probably a leak or a front height sensor.

Had this issue as well. Problem was with airbags and compressor. Ended up replacing air ride suspension with coil springs.

Replace the air suspension with conventional shock/strut
conversions. The Air Ride System is not worth investing
time and money ,after the vehicle is 5 years old.
Too expensive to maintain ,and too difficult to diagnose

Next time buy the Ford version of the vehicle

My suggestion to you and all the other folks leaving questions on this board about collapsed air suspension systems in luxury cars is to fix that one by replacing it with a real spring and shock system which you can buy at www.strutmasters.com if it is economically feasible, then sell it and avoid air suspensions systems like the plague. There are legions of old 70s Citroens still sitting idle 30 years later on collapsed air suspensions systems in garages and barns all over the country which cars the buyers can't let go because they cost so damn much. Get a coleman air mattress and use it every day, see how long it really lasts.

THE NO 12 REASON FOR THIS IS THE AIRBAGS FOR THE SUSPENSION ARE LEAKING, U CAN REPLACE THEM WITH A NON AIRBAG KIT. GO TO THE WEB LINK FOR DETAILS.
http://www.suncoreindustries.com/english-lincoln-navigator-03-06-air-suspension.html

Check all your fuses. in the dash if any and in the hood if any. Sounds like the circuit overloaded and shorted out.