Hi have a cooper r50 2002. Experiencing electric problems. Brake lights sometimes don't work. Abs and tyre pressure warning lights sometimes are on sometimes not. Speedo stopped working then started again. If I use remote to lock car the windows and sunroof open. Suspect bc1. I'm looking to replace it with a 2nd hand unit. Having read various threads I'm confused.

Do I just replace bc1 or all ecu's keys locks etc. any help would be welcome