2000 Expy EB - basically the same as yours.
Primarily three components:
1. Air compressor under the hood by the window squirter reservoir,
2. Solenoids,
3. Air bags.
I had some sag in my rear and ordered all the parts to replace the bags - bad decision. Could never track down why the bags wouldn't inflate. The compressor turned on, but no air to the bags.
Took everything out and installed a spring conversion kit from Monroe. Cost was around $400 from O'Reily's. Shocks were easy. The rear springs require compressors. Passenger side, no problems. Driver's side is a different story because of the fuel tank.
Highly recommend doing to coilover conversion. Read this -
https://www.expeditionforum.com/threads/air-suspension.15692/ - then post questions as needed.
Good luck
