1997 540i OBC is not working

I'm having all kinds of problems with the OBC in my 1997 540i. 1) Some of the pixels on the check control indicator at the center of the instrument panel are lighting randomly and with different intensity, so it's almost impossible to read/understand the data. 2) The OBC only displays data related directly to the buttons located below the nav-system screen -for example "rate of fuel consumption" or "time to destiny". 3) No warnings or data regarding the operation of the car are displayed -for example if the seatbelts are not fastened or if the car is turned off with the lights on, etc.
I've been told that these problems are frequent on the 1997 540i, and that no repairment is available. It seems that the only solution is to install a new OBC. I will really appreciate your comments and alternative solutions to solve these problems.