4x4 high and 4x4 lights flashing on 2003 expedition?

Answer 1

As you can see below, there are so many possibilities it's nearly impossible to diagnose over the internet. You might try a search to see if others have had similar symptoms to yours.

Transfer Case

PINPOINT TEST A: THE 4X4 INDICATOR FLASHES WHEN THE A4WD MODE IS SELECTED - 4X4 INDICATOR

Note:
The vehicle has to be driven in A4WD 30 mph or greater and/or encounter a slip condition before the 4x4 lamp will flash for certain faults.

Note:
Complete the entire pinpoint test related to the symptom before replacing the GEM.
² A1: CHECK THE IGNITION STATES
² A2: RETRIEVE THE RECORDED GEM DTCS FROM BOTH CONTINUOUS AND ON-DEMAND SELF-TESTS
² A3: CHECK THE 4WABS MODULE INPUT; 4WABS MODULE CONNECTED - MONITOR THE GEM PID PWR_RLY
² A4: CHECK THE 4WABS MODULE INPUT; 4WABS MODULE DISCONNECTED - MONITOR THE GEM PID PWR_RLY
² A5: CHECK CIRCUIT 239 (WH/OG) FOR SHORT TO POWER
² A6: CHECK HALL EFFECT POWER CIRCUIT FOR SHORT TO GROUND - MONITOR THE GEM PID HALLPWR
² A7: CHECK THE HALL EFFECT CIRCUIT FOR SHORT TO GROUND - TRANSFER CASE ASSEMBLY C1019 DISCONNECTED
² A8: CHECK FRONT AND REAR HALL EFFECT SENSORS
² A9: CHECK CIRCUIT 774 (LG) FOR SHORT TO GROUND
² A10: MONITOR THE FRONT AND REAR HALL EFFECT GEM PIDS TRA_RSP AND TRA_FSP
² A11: CHECK THE VOLTAGE TO THE HALL EFFECT SENSORS - CIRCUIT 774 (LG)
² A12: CHECK CIRCUIT 774 (LG) FOR OPEN
² A13: CHECK CIRCUIT 682 (DB) FOR OPEN
² A14: CHECK THE VOLTAGE TO THE HALL EFFECT SENSORS - CIRCUIT 774 (LG)
² A15: CHECK THE HALL EFFECT SENSOR GROUND CIRCUITS 682 (DB) FOR OPEN
² A16: CHECK CIRCUIT 435 (YE/LB)/722 (LB) FOR OPEN
² A17: CHECK CIRCUIT 435 (YE/LB)/772 (LB) FOR SHORT TO GROUND
² A18: CHECK CIRCUIT 435 (YE/LB)/772 (LB) FOR SHORT TO POWER
² A19: MONITOR THE TOD RELAY GEM PID 4WDCLST
² A20: CHECK CIRCUIT 976 (OG) FOR SHORT TO POWER
² A21: CHECK CIRCUIT 976 (OG) FOR SHORT TO GROUND
² A22: CHECK CIRCUIT 976 (OG) FOR OPEN
² A23: MONITOR THE GEM PID 4WDCLST - REAR WHEELS BREAKING TRACTION
² A24: MONITOR THE GEM PID 4WDCLST FOR ON--- RESPONSE
² A25: CHECK CIRCUIT 976 (OG) FOR SHORT TO POWER
² A26: CHECK THE A4WD OUTPUT
² A27: CHECK CIRCUIT 779 (BR) FOR OPEN
² A28: CHECK CIRCUIT 779 (BR) FOR SHORT TO GROUND
² A29: CHECK CIRCUIT 779 (BR) FOR SHORT TO POWER
² A30: CHECK TOD RELAY CIRCUIT 57 (BK) FOR OPEN
² A31: CHECK THE VOLTAGE TO THE TOD RELAY - CIRCUIT 704 (DG/LG)
² A32: CHECK THE VOLTAGE TO THE TOD RELAY - CIRCUIT 294 (WH/LB)