i have a 2001 F150 five speed. 4.6 L. i have the offroad package with shift on the fly, but its pretty much useless right now.

If i engage the four high, nothing happens. If I engage the four low, it will engage in the rear wheels only, and low range light comes on.

any suggestions?

 

Not sure what you are talking about? Obviously the rear wheels are always driven in 2wd or 4wd.

 

If its in 2H it functions normally. If in 4H, no difference. If in 4L the back wheels will engage in the low range, but not the front tires.

 

Your IWE's are probably shot. (vacuum operated)

If it's electronic then the solinoid is probably bad.

I don't own one but those are my best guesses.

Is this a previously owned truck?
Did it ever work for you before?
It is also possible, if it is a used truck for you, that the spiders are completely blown out of the front.
Could also have a broken axle.
Does the front drive shaft turn when you shift into 4WD?

Start with the easy stuff and work up from there.

Good luck.

 

2001's don't have IWE's.

 

That was a guess, glc. There are alot of questions to answer before he can pin point the issue, just trying to nudge him along. Thanks.

 

took me a while to get back to this, but as it turns out it was my GEM module. water leak caused a short.