1997 Ford F150 four wheel drive

148,967 MILES • V8 • 4WD • AUTOMATIC
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JFASTOR
  • MEMBER
  • 1 POST
It won't shift into 4h or 4L when you flip the switch. Checked all the fuses they're good. checked the wiring is fine.What can be ? How can the switch be checked?
Apr 27, 2009 at 10:32 AM
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DAVE H
  • ✓Experienced Mechanic
  • 13,383 POSTS
Have the vehicle plugged into a diagnostic computer it should be showing a fault code !!

Vehicle Does Not Shift Between 2WD & 4WD High Modes Properly
Possible causes: 4WD mode switch, 4WD clutch relay, contact plate sensors, T/C shift motor, transfer case and/or GEM. Go to TEST A under TESTING.
Vehicle Does Not Shift Between 4WD High To 4WD Low Properly,
Shifts Properly Between 2WD To 4WD High, 4WD High To 2WD
Possible causes: 4WD mode switch, vehicle speed sensor, BOO switch, transfer case, TR sensor and/or GEM. Go to TEST B under TESTING.
Front Axle Not Engaging Or Disengaging Properly
Possible causes: 4WD solenoid, 2WD solenoid, vacuum motor, vacuum lines, front differential and/or GEM. Go to TEST C under TESTING.
4WD LO &/Or 4WD HI Indicator Light Not Operating Properly
Possible causes: light bulb, TR sensor and/or GEM. Go to TEST D under TESTING.
4WD HI Does Not Engage At Speed Properly (Driveline Does Not
Synchronize Properly) But Does Engage At Rest
Possible causes: ESOF clutch relay, internal clutch, hub release spring and/or wiring harness. Go to TEST E under TESTING.
No Communication With GEM
Possible causes: Fuses, harness and/or GEM. Go to TEST F under TESTING.
Apr 28, 2009 at 9:40 AM
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