2004 ford explorer 4.0 and I have a p1825 code.. I looked at the ground wire next to the transfer case and that wire is fine... while driving the 4x4 light flash sometimes and yes the transfer case does go into 4x4 high and 4x4 low... says relay could be bad but I dont see relays for the 4x4 clutch..

 

Check your owner's manual , pages 191-198.
Should show relay and it's location.

 

I did but dont see it... I see 4x4 relays but nothing to do with clutch...

 

Only control relays for shift functions are two out in the engine compartment box