First, I am hardly the expert you are looking for. All my information is based mainly on what I've read on various forums and dedicated automotive websites over the last 8 years or so. The limited personal experience I've had with the subject at hand consists of the dealership changing the BCM on my 96 GC for a wiper problem many years ago and fixing an acquaintance's erratic instruments by re-soldering the mentioned cluster solder joints on his 98 T&C. There are experienced techs on this forum. Hopefully they will chime in or I should say keep chiming in.
1) It reveals there is a communications problem on the PCI data bus.
2) Your dash should have an "alarm" light that blinks several times as the system arms. Turn the key to on/run. All the dash lights should light up. You may see it then. Ask your dealership. They should be able to tell by the VIN # or some other source.
3) Yes! If you swap a BCM programmed with a security system into a van without one or visa versa, it can effect the PCM and keep the van from starting.
4) As to flashing - I don't know. Chrysler dealerships change BCMs all the time. The VIN# and mileage have to be reset every time otherwise there would be thousands of vans driving around illegally with modified mileage figures. I believe that's a function of their DRBIII scanner.
5) Yes, I see the logic. I've read about many doing the same. As mentioned watch the security system match up. As far as the cost, kind of a catch 22. That's $75 that could go towards having this done at the dealership. Then again they could change it and not fix it and still charge you. Then again, this problem sure sounds like the BCM is the problem. There are other possible culprits and I'm thinking of the previously mentioned A/C Heater control panel (HVAC panel) connection and the single data bus wire
that connects everything on the data bus. A poor connection/damaged wire anywhere on the bus can effect the entire bus or just parts of it. See my previous post and take note of Tizzy1s PDC thought.
Here's one thing you can do in your driveway. Read and try post #16 titled "DIAGNOSIS AND TESTING - SELF-DIAGNOSTICS" in the "Tizzy1 and others DIY" thread at the top of the forum. This will test all the instruments and lights on the cluster. If this works consistently it may indicate your cluster is good.
Your second post about the radio and wipers points to the data bus and could be the BCM. **Just remembered another problem spot**. It just fixed a very similar problem for someone on another forum after several visits to a dealership. It concerns the wire bundle at the bottom of each power sliding door (if equipped). Disconnect each one at a time and see if it cures anything. As I said earlier - " There are other possible culprits... and the single data bus wire
that connects everything on the data bus. A poor connection/damaged wire anywhere on the bus can effect the entire bus or just parts of it".
If you don't get your answers here try www.chryslerminivan.com