Hi everyone, I need some help with my esop.(2005 f350 psd)

I'm having an issue with my esof.About a wk ago stopped working.Proir to that it had been working but I think one side wasnt engaging properly(hub lock).After the last snow fall,I had been using it during the snowfall,then the next day as I was out I noticed that when I would switch it to 4H or 4L,the light would not turn on and I could feel that it wasnt engaging.

So then I spent some time reading up on several posts , on trying to resolve the problem. I went through all the fuses under the dash,removed n checked for conditunity,checked the ones under hood, checked the the 2 relays on their own next to the battery(replaced them) swithed the transfer case motor(used) tested the wires to the motor(cond. ok) tried a test light to the two prongs,while turning the switch to 4H nothing,went back to the relay box removed it from the fender n placed the test light on the 2 wires that run down to the motor n didnt light up.

Q.= Am I missing something in that chain??

Is their a module somewhere their that I'm missing?? (location??)

I've been out today checking over the vacuum. Seems fine dont see any cracks,and the connections look good.

Thanks to all that had posted their solutions, that I had a chance to read and utilzed .

Would like to get this fixed have more issues to take care of.