If you can change out an alternator, you can switch out the air bags & change the solenoid. I did my 98 navigator's at 6 years old. I would start at the solenoid first, check wires (wiggle them) if the system does not work at all and idiot light is on.
WHAT WIRES DO U NEED TO CHECK ON. THE TRUCK GOES INTO OVERDRIVE WHEN I START TO ACCELERATE, IT THENS JUMPS TO A HIGHER GEAR WITH A JOLT. SHOP WANTS $500 TO REPLACE SOLENOID. ALSO THE CHECK SUSPENSION LIGHT IS NOW ON DURING THE RIDE. HELP WITH ANY ADVICE