You replaced the Lincoln Navigator air suspension compressor and it still won't come on?
Because the way the factory Expedition & Navigator air suspension compressor is built, they consume more amps than any other Ford/Lincoln compressor of comparable size and they are extremely hard on 2 things. One is the armature inside the electric motor part of the compressor and the other being the power supply, which is the compressor relay.
When the armature goes bad, the power consumption can increase and require even more power from the relay. These relays are a solid state design and don't do a very good job handling such a large current load and will usually be damaged.
With that being said, if you have replaced the compressor and it won't run, check for power at the compressor within 90 seconds of turning on the ignition. (after 90 seconds, the module will time-out and give up)
Don't worry, you didn't replace the Lincoln Navigator air suspension compressor for nothing. You may have temporarily gotten it working again by just replacing the relay, but because the compressor was actually what started the problem, the new relay would be damaged in a short time if the Navigator air suspension compressor hadn't been replaced.