'06 TL Blu Tooth drains battery

My wife's 'o6 TL's Blu Tooth board drains the battery if the car is not used for a few days. I disconnected the board and this solved the problem with the battery drain. My wife now wants her blu tooth back.
I know that this is a common problem on '06 and other year TLs. Are the newer boards free of this problem.The removal and install of a new board does not look that complicated but, I don't want to invest in a new board and have the same problem again.

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