07' Lexus IS-350

I've been searching the threads with little luck to my issue.
Yesterday the headlights started switching between low and high beam on it's own.
First it would do it about every minute and grew to do it every few seconds.Now the headlights are stuck in the "High" position and won't dim.
I checked fuses and relays but can't find any problems.
I suspect a failure in the Multiplex Body Control Unit # 89211-53010.
Does replacing that unit sound like a reasonable option ? I've not found any other relay that works the high and low beams.
Any input is much appreciated.
Thank you,
Sp0iler

Update: Changed out the Body Control unit with no success.
I need input from the Guru's. Where are you guys at ?
Thanks for any input.