So, after removing the seat and immobilizer last night and opening the immobilizer and seeing the fried board and components, I decided that I would I get out my trusty Power Probe III circuit tester and a spare 12v power source this evening . With the chassis circuit diagram in hand to read to determine the correct immobilizer plug output pin on which to connect my Power Probe and supply the pin with the correct signal (either power or ground), I was successful in actuating all controllable units. The door locks, windows, convertible top, frunk lid, trunk lid, all open/close/lock/unlock and I now have a battery charger on the car battery.
The carpet/foam under the seats/seatbacks are wet and I have now placed hairdryers between the carpet and the floorpan to dry them out. The foam under the carpet is extremely dense and is holding a lot of water. I have squeezed the foam multiple times and scooped out the water collecting in the floor pan and I probably got half an ice cream bucket out of the driver side pan. It might take a few days to completely dry out the carpet which is fine as the new immobilizer and two key transponders (I will reuse the two cut keys that were with the car) I just ordered will not be here until early next week.
As a side note, I highly recommend any car enthusiast having a Power Probe in their tool arsenal. Using one is invaluable to me in testing circuits to find where the failure points are. Before I had a Power Probe I would routinely use the ‘shotgun approach’ and change out what I thought was the bad part only to find out it was something upstream/downstream in the circuit from the part I changed out. Sometimes the last part changed was the culprit. The Power Probe has paid for itself numerous times in precluding the purchase of electrical parts that are not returnable after installation.
Tomorrow I will inspect the chassis drains and I guarantee some/all are plugged.