Air suspension inactive. Fuse ok. No light on dash switch. Ideas?

This is a bit old but for the future, turn the steering wheel from full lock in one direction to full lock in the other. Yes, it's weird but that's solution.

A malfunction with the air suspension system has been detected
Start with the basics and check the switch in the right front passenger footwell , by the kick panel and see if the air suspension service switch has been turned off , or perhaps its fuse # 12 ( 15 amp ) for the air suspension switch , or fuse # 15 - 5 amp for the air suspension module ( but unless you have noticed other things not working it's probably not that fuse ) In the power distribution box in the engine compartment
( Ford states to disconnect your battery before servicing anything in the PD BOX ) fuse # 109 is a 50 amp maxi-fuse for the air suspension compressor , or it could be a sensor or the compressor itself etc.

Call tire and muffler shop (or any shop that replaces suspensions work) it's probably a reset somewhere.

Hello
Since you're looking for fuses and relays, I will assume that the compressor is not working. First check the suspension service shut off
switch located under the right side of the dash. If thats on, go to the fuse block under the left side of the dash and check fuses #4-#5-#20-#2
If they're ok, move to the fuse block under the hood on the left fender and check fuse #109 a large 50amp fuse it's best to use a 12v test light.
If that checks out, check the compressor relay located near the right
headlight assy. there will be 4 wires from the relay, lt blue/pink(hot to fuse #109) lt green/red(grnd to compressor) grey/red pwr to compressor)
drk blue/yell to suspension/steering module located behind ctr of dash.
Before you start these tests turn key to on(should be on for all tests)
use the 12v test light and test for power from grey/red wire at the
compressor + check lt grn/red wire for good ground. If you have pwr+grnd it's most likely a bad compressor. But if no power perform the
above tests. Hope this helps.

inactive air suspension is displayed
no lights on at switch

make sure the switch is on. it should be in the trunk area. if thats not the problem, there is probably a leak in that shock. they are known for this problem after about 5 years.

Humming sound is from the front plastic cowling on the outside of the car, at bottom of windshield, This plastic cover warps over time causing the sound. A little silicone adhesive to tack trim down will alleviate the noise.
2. Air suspension inactive light can illuminate for multiple reasons, To avoid unecessary expense the car should be scanned with a land rover scanner (dealer or aftermarket (expensive) unit)). The compressors do go out, Compressor is the domed shape unit under the spare tire.

Air Suspension Inactive usually means there is a problem with the Air Suspension. However, it will also come up when alternator or battery voltage is low, or when you reset (disconnect and then connect) the battery. To reset it manually: while in P(ark), turn steering wheel all the way left, hold few seconds, and then all the way right, hold few seconds. All the warning lights will go out. Most common failure is the passenger front air strut, since batteries are prone to leaking acid, it leaks right on top of the rubber airbag and burns through it. Dealer willcharge you one hour to diagnose, or you can easily diagnose this by looking at the ride height of each particular corner of the truck. If its sits low, or emits hissing sound when you park the truck, its leaking. If you keep driving with leaky air strut, you risk burning up the air compressor, as its working extra hard to compensate for the leak. Replacing the strut is easy 45min job even for a novice mechanic, and you can do it yourself. Strut can be found new for approx $750 online. If you are fed up with air suspension issues, there is a $700 kit that converts the truck to springs, and disables all of the air suspension. Look up Arnott Industires

SIMPLE SOLUTION :
Turn engine on, without moving the car, turn steering wheel from one extreme side to another 4 times, message "air suspension inactive" should be over now (; ])