Yes, I left the sunroof open on my 05 MCS during a torrential downpour Sunday and now I'm having some electrical issues. I'm looking to find out if anyone has had a similar experience and what can be done without taking it to the dealer. Here's my issues

1. My flat tire sensor idiot light is on. (I checked the tires. Pressures are all within 1 lb of each other.)
2. My airbag idiot light is on.
3. The keyfob remotes no longer work. (the lock switches still work though)

I immediately dried out the interoir using towels and heaters. I then removed the rear console and tire sensor reset switch and dried that out with a hair dryer. That seemed to work for a while but the light is back on again. I'm pretty sure it will go back out when the switch dries completely.

However, I'm not so sure about the airbag light and key fob. I checked the fuses and they're fine. I think there is some kind of airbag sensor under the seat. If there is, then I'm sure that got wet as well. The key fob remote is a complete mystery. Any advice?

I should probably add that the airbag light came on after I removed the drivers seat to dry the carpet underneath and make sure that the underside of the seat was dried out. (the wife and I are allergic to mold) The light came on after I unplugged the three harnesses attached to the seat. It wasn't on initially after the soaking. (I think I need my own personal idiot light)

Just a WAG but maybe needs a computer reset ( reboot ?) by the dealer?

Good Luck

On Edit... I know you said without the dealer, but so much of the car is electrical and is ran by the computer hard to think that is not a good starting point once the car is good and dry and is still having issues.

( gezz... can't believe I have to start off in Neutral... course at least it's not Reverse..

make sure you let it dry very well, i had sorta the same problem in a different car of mine, sunroof wasnt open but came out the next morning after a serious rain fall to find about 1ft of water in my car. it had a couple of odd problems at first but once it dried out after a couple days everything cleared up

Yeah, I figure I can't do any more damage just by waiting it out. Unfortunately, it hasn't really stopped raining since this happened, so it's taking longer to dry out.

Left the sunroof open on my 03 last summer and sure enough it rained at the exact time I could not get away to go close it.

My only side affect was that the drivers seat heater was energized even though the switch was not on. So for at least 2 days in July I had to drive around with the seat heater on. After those couple of days, it returned to normal operation.

Any idea if he/she can clear these codes by disconnecting the + battery terminal for a few mins like the old days ?

Unplugging the seat airbag harness does trigger the airbag light (definitely if the key is in the on position; not sure if completely off). The general recommendation is to disconnect the battery before unplugging/removing front seats, exactly to avoid this problem.

Once the airbag light is triggered, it will not turn off until reset by the dealer (or a shop with a reset tool).

That's exactly what I did. After I unplugged the tire sensor reset switch and removed the driver's seat, I then turned the key on to see if the tire light went out with the switch removed. It did, but that's when the airbag came on.

So you're saying that unplugging the battery won't do any good? Oh well, I guess It's off to the dealer then.

Thanks everyone for your responses.