Hi there. I have a 2000 Ford F250 with the 7.3L power stroke. The 4x4 on the truck does not work at all, no 4x4 light, no clicking sounds, nothing. All the fuses and relays are good, 4x4 switch is good, everything is working good on the truck other than the 4x4. Any suggestions on what it might be would be greatly appreciated. Thanks

 

That should have manual locking hubs, turning the inner section both wheels clockwise should allow it to engage.

 

Welcome tot the site..
With ESOF,,
If you've checked all the circuit protection, relays, its possible it could be a GEM issue. Was fairly common for windshield leaks to allow water intrusion to migrate down and into the GEM, with/without opening fuses. May not be the case/cause, but we could send you the full system schematics to verify power distribution points. an aid in looking for drop outs as well.

 

I went through the Ford pin point test for the 4wd circuit. The test for the solid blue wire on the gem connector says, “if there is power repair the short in the wire. If there is no power replace the gem module.” I don’t understand how if there is no short, the gem module is bad.

 

Not sure what kind of hubs you have on that model year, but I have a 2004 F-250 crew cab that was having the same issue, although my light still worked. I have the shift on the fly issue and my hubs are both manual and auto locking (you can select both on the hub). My issue was although the light on the dash lit up when 4wd was selected, it did not engage. I ended up taking it to the dealer that discovered that both my actuator and solenoid were bad. After being replaced everything worked find for about a year before same thing happened. Back to the dealer I went and they checked their repairs (Ford has a 2 year unlimited mileage warranty on their repairs) and this time the vacuum hose was old and leaking which would not allow sufficient vacuum to engage the 4wd. Now i'm back on the road just in time for more snowy roads.