4x4 wont engage?

[rdmcgreanor]

Awhile back i drove threw a huge puddle of water ...and rite after my Brake light was on solid and the 4x4 light was flashing and won't engage. The 4x4 light flashes in 7x intervals. The brakes are new and all the fuses are good the only code in have is No Communication with the ABS module... where do I go from here?
2005 ford expedition limited

 

[whtbronco]

You actually provided the answer in your question. "No Communication with the ABS module". The overly complicated 4wd system on modern vehicles requires input from numerous systems to function correctly.

Communication and the correct signal from the transmission, wheel speed sensors, PCM and ABS is required.