Passat B5 dashboard

[Michael0]

Please I need help, my problem with dashboard on Passat B5 TDI AFN 1998 dashboard work but when try connect any diagnostic interface can not connect, K line in instrument cluster is short to ground, ( if remove coonector from IC Cluster have normal diagnostic conection to ABS, Airbag atc, all controler without dsahboard and ECU), I replace dashboard with used dashboar but after maybe 3 mounth same error come again.

Thanks in advance
best Regards Michael