2017 mercedes atego electrical issues

[Scottieg1]

Hi everyone. Hoping someone can point me in the right direction. Last week, my midicoach sat over the weekend, i came out to it being flat on the monday. I put charger on and after 10 mins charging it started. However, later that day the the brake and driving characteristics lights came on. After that, its like the dash lights and tacho stays on even tho the keys are out. Checked the on board diagnostics and it tells me to replace relay k2 or repair and next service interval. Also tells me that electrical supply restricted… any ideas anyone