dash cluster on my 2004 D12 volvo

My Volvo had a water leak from the windshield trim, water was getting past the mounting screws and dripping down the A pillar causing corrosion to build up on some of the wiring connectors behind the dash by the firewall. Took the connectors apart and cleaned them with electrical terminal cleaner, found and sealed the water leak and no more problems.

Your problem may be snow/ice buildup on a wiring harness pulling a connection apart, check along the top of the transmission, I also had a wiring harness issue there that caused many problems in my cab resulting in a data bus error code. I ended up replacing the entire harness from where it connected at the firewall out to the engine, transmission, and back to the relays on the frame crossmember under the cab because water had entered the harness and corroded several spots. I hope this is not your problem, the harness was almost $6,000 plus labor to install, expensive repair.

 

try the big 3 or 4 big plugs on the side of the engine wiring harness unplug them and spray some contact cleaner in them that is a data link code