Hi Gents,
Strange issue with my G. After it rains, the car stops sensing the key. First time it happened, it eventually started but stayed in 1st gear and WOULDN'T shut off. I drove slowly to nearest mechanic who stopped it somehow and charged $700 for 3 hour check of all modules.
A month later, same issue. This time had it towed to dealer. They found no water leak issues or module problems. Replaced few battery cables and harness near battery. $800 charge.
Two days later, same ****. I also notice very high pitch constant beep near battery with engine off. Planning to tow it back to dealer and make a scene.

 

 

Yep, definitely sounds like the IPDM is wet. Cover probably didn't get put on correctly or your cowl drain (area around the wipers) is plugged and not draining water so it ends up on the IPDM.