4×4 and fdw lights flash and the truck won't engage 4×4

I left the key in the ignition switch, switch on and the next morning the 4×4 and fwd lights flash. The 4×4 don't react if I select 4h or 4l.

I had the truck at a Ford dealer to scan for codes, no fault codes.

How can I test the Esof module.

Thanks

JJ ( from South Africa)