I recently bought an ’04 5.4 l triton v8 F150 Fx4. I’ve noticed when I put the vehicle in 4x4 hi the light does not come on which indicates it’s in 4x4 hi. I know the light works because it comes on along with all the other lights when I first turn on the ignition. I can’t tell for 100% sure that it’s going into 4x4 hi. I’ve tried it out some, and it sort of feels like it’s working, but I haven’t wanted to play with it very much on dry pavement. The 4x4 lo light works and I can definitely feel when that engages. I asked the previous owner about it and he said the light stopped working when he put 35” tire on, but the 4x4 still works. Any ideas?

 

Changing the tire size wouldn't affect the light.

Also, if it isn't shifting into 4HI it can't hit 4LO. The switch to turn on the 4HI light can only be activated if the transfercase actually shifts.

A common problem is that the shift motor gets stuck if it isn't used often. The way to fix this is to switch it into 4HI then get under the truck with a hammer and give the motor a few taps.

 

I guess my first question is if it's possible that it is shifting into 4x4 high but the light simply isn't coming on? That is what I think is happening. And if that's the case, it's fine, I don't really care about the light. I just want to know the 4x4 hi is working before next winter.

I suppose it must be, since you say it couldn't go into lo if it isn't getting into high. I know 4x4 lo works for sure. I can feel it, and that light is working.