I noticed that " Helpfull " had answered that the air suspension relay on a 1998 Ford Expedition was located on a bracket by the passenger side headlight . ( he came up with the answer after doing a Google search about 21 hours ago - was the answer not correct ? )
under the hood on the left front, it looks like a large fuse box.
the relay for the air suspension is under the hood in the fuse box and its number 4. I just changed it on mine.
under the hood, passenger side in front of windshield fluid its a black box the size of a quarter.
The suspension compressor relay on the 1995 Lincoln Continental is located under the hood in almost the exact center of the vehicle just under a smaller relay. It is at the front of the car, just look for the fan shroud and the relay will placed in between the two fans closer to the top.
The horn relay on a 2001 Ford Expedition is located on the RPO Relay Block 1. You can find this relay block under the dash just above the passenger-side air bag.
On the 99 it is in the corner passenger side under the glove box. There is a switch that to see you have to get down in the floor board, look to the very corner, you should find it. Good Luck, that is the location of the switch not the relay. the relay is on the front pass. side behind the fender under the head light.
on a 1998 it is located under compressor r/f fwd wheel well
Under the hood, black box, Fuse #12 also has relay (#4)
It should be located in the Trunk near the right side. If it's not there, it's probably located under the hood with the other relays. hth
On the passenger side behind the wheel well liner to your right, silver with fins.
The pump should be located next to or under the windshield washer fluid reservoir. You will need to remove the reservoir, then the compressor will have 3 screws, the electrical connector and the air line holding it in place. Be sure to seal the airline while you have it off to prevent contamination.
Its under the dash on the passenger side of the truck. juat a few screws very very easy