I'm sure y'all have seen a 100 posts like these, and I've probably already read them all, to no avail. If this has already been addressed, please point me to that thread.

I have a 98 F150 (5.4) with the dash **** 4wd. when I turn the **** from 2hi to 4hi/lo, nothing happens. No clicking, no dash light, nothing. when the problem first happened it would work occasionally (like 1 out of 5 tries), now it doesn't work at all. Ever.

Everything I'd read said the most common problem is the transfer case shift motor, which I replaced. Still nothing.

I don't believe it to be a vacuum issue because, from what I've read when that is the problem, the dash light will still come on b/c the transfer case was shifted, the hubs just won't engage. But it my situation I don't believe the transfer case is shifting to begin with.

I've checked the 2 fuses, the one under the hood and the one under the dash - they are fine. I'm stumped.

Any suggestions?

 

have you tested the switch? switch failures arent common but also not unheard of

 

I haven't but that's my next step. I should have done so before replacing the shift motor but I just KNEW that was the problem.

I'm going to test the switch, the plug coming to the switch to make sure it's getting power, and the plug going into the shift motor to make sure power is getting from the switch to the motor.

 

A very simple resistance check of the switch... 360 Ohms, 1.1K Ohms, 3.0K Ohms= the three positions of the switch. After that you either have a bad GEM so it's not controlling the shift relay in the dash. Or the shift relay it'self is bad.