2003 Ford F-150 4 Wheel Drive

Have you found a resolution to your problem? I'm currently experiencing the same issue. When shifting in to 4 High, sometimes it works, sometimes it doesn't. The light comes on, and stays on while the shifter is engaged, but it randomly slips in and out of 4 high. Also checked it in 4 low, and didn't work.

I am having the same type of problem. My 4X4 truck light comes on for no reason at times. It seems to turn off at will. I think it may be a relay switch. But I probably need to bring it in to the dealer to have him diagnose it. It seems like a lot of Ford owners are having the same problem.

I'm going thru the same issue on an 03 FX4. What i've found out so far is that it is a vacuum system. You need to run a vacuum check on the line that runs from the vacuum solenoid, mine is on the fire wall behind the battery, down to the vacuum pump on the front diff, if that holds, the solenoid may be bad. I have already replaced the solenoid on mine, about $50 at the dealership only. If you go to a parts store and buy a $20 repair guide ( Haynes or Chilton), it will show how to check all of this. You can also get a vacuum tester at AutoZone ( loan-a-tool ) for a $50 deposit that you will get back when you return it, good luck.