Can't Duplicate!!!

I don't want to bore you with every detail, so let me be brief...
A customer with a '98 Caravan has been in 3 or 4 times over the last nine months with a complaint that her dome light comes on randomly, her gauges go to zero and then go back to normal and her wipers go on occasionally. These things don't all happen at the same time and I think they happen very rarely.
We have NEVER been able to duplicate any of these problems. But under pressure we have replaced two BCMs, a multifunction switch, and a wiper motor. We have tediously inspected the main wiring harness and inspected numerous other electrical connections.
Our owner has spoken with her and has asked the Service Department to get the vehicle back in and figure out the problem. We intend to give that our best shot.
A couple questions: 1) What are your thoughts in general about this case. 2) Any thoughts on what might be the problem?
A customer with a '98 Caravan has been in 3 or 4 times over the last nine months with a complaint that her dome light comes on randomly, her gauges go to zero and then go back to normal and her wipers go on occasionally. These things don't all happen at the same time and I think they happen very rarely.
We have NEVER been able to duplicate any of these problems. But under pressure we have replaced two BCMs, a multifunction switch, and a wiper motor. We have tediously inspected the main wiring harness and inspected numerous other electrical connections.
Our owner has spoken with her and has asked the Service Department to get the vehicle back in and figure out the problem. We intend to give that our best shot.
A couple questions: 1) What are your thoughts in general about this case. 2) Any thoughts on what might be the problem?