I have a 2012 Vivaro which has come to me with an alarm/interior light fault. It has previously had a body control module but it has not cured it.

Intermittently the interior light will illuminate whilst driving along as if a door has been opened but all door switches remain inactive on data display. Also the alarm will occasionally go off when the vehicle is parked up.

I've done the obvious checking door switches and door looms but all seem fine.

There is a permanent code in the body control module which is 'no CAN bus communication with instruments'. Unfortunately I'm also struggling to find a wiring diagram.

Any help much appreciated!