Freightliner century 07- no datalink

hello guys, posting here for the first time and hoping my long standing problem will be solved. I get this message 'no datalink' on my century 07 dashboard. As a result, all the guages except for the air pressure stays at mark zero. I read different forums and posts amd tried most of the methods but to no avail. This error popped about a year and half ago and comes up once in a while and goes away just like that.

Today I disconnected the cable which goes under the cab to the connector which i assume is
to the panel behind the seat on driver's side. All guages came up. I reconnected it and same problem occurs. Along with this gauge problems my radio, ac and none of the cab lights work.

Thanks in advance. Hope to hear any suggestion/advice soon.