Monday rain and after work, I unlocked my car parked in the lot and there was approximately an inch of standing water on the drivers side of the passengers compartment. I bailed it out, drove home. Then Tuesday, the rain was worse! And as it turns out the standing water was even higher! I bailed it out again and started it up to drive to my 2nd job. As I drove I began to notice that something was amiss. Dome light went on and off, temperature gauge spiked and went back down. After 15 minutes of driving there was standing water in the car again. I arrived and bailed it out again and went to work. After a couple of hours, it was dead. Apparently an outrageous amount of leaves had clogged drains (???) and now electrical damage will likely have totaled the car. Who knew there were engine drains that needed to be regularly unclogged?
Not engine drains, but drains in the air intake in front of the windshield. And yes, leaves can clog them up. Once water gets into the interior lots of bad things can happen, as you’ve found out.
It can also be clogged sunroof drains that cause this. The reason your car went crazy is because in all likelihood the ECU (the car’s brain) is under the passenger side carpet. Water and ECU’s cause interesting results.
With that little water, and isolated location, I really don’t see why you can’t just replace the computer and check the wires.
I’m wondering how given that I have religiously had the car maintained by the same mechanic since I’ve owned it (5+years), and that I have previously owned three other cars with sunroofs, and that I have never in my life had garage to park in and therefore subjected my cars to all kinds of environmental hazards like leaves, and that I have never experienced this problem or known of any other person to have this problem, how an issue like this can be so serious without any previous caution or warning. I mean I can’t know to check for something or request something be checked, if I am ignorant of the possibility of its very existence. I’m disappointed that when I’ve paid someone to maintain the car that they don’t at least give me a heads up that a problem like this could occur, be potentially catastrophic and that I should be taking steps to avoid it. Mind-reading, sadly, is not one of my talents. Thoughts? How did I miss the memo on this?
Is this a VW?
Shops would rarely see a sudden, catastrophic failure due to a plugged roof drain. Usually when the drains plug the customer complains of damp carpet and foggy windows and the shop cleans the drains and informs the owner to avoid the leaves in the future. Warning owners for all possible scenarios would require an epic novel, not a memo.
I mention VW because there’s a class action lawsuit regarding drains and damage. Happy to send you the specifics it is applies.
Make, model, year, mileage, would all be very helpful for this and any other car question…Also with cabin leaks, does it have a sunroof that opens??
Did insurance cover the damage?
This is a 13 year old thread . Being new you can see on your screen to the right hand side the date of last post.
I doubt Rees will respond . If you have a problem like this only your insurance agent can answer if you are covered.
Please stop infecting threads with logic/ reason. I demand it!! 
I discovered that same problem on my truck some years ago. Water intrusion caused by blocked drains. Most vehicle owners never notice these drains, but the drains are designed by the manufacture to be pathways for rain water that hits the windshield and roof to quickly flow to the ground rather than inside the car. In my case the truck was parked under a tree too long and tree leaves and twigs clogged the drains. Parts of that pathway are very inaccessible, so It was a big job to re-open them . Since then, to avoid having to face that job again, I’ve been vacuuming the debris that accumulates under the windshield (open the hood too) and in the accessible parts of the drains on every oil and filter change, and never had a water-intrusion problem since.
I test the drains every once in a while too, on a dry day, by spraying water on the top of the car and making sure some of it comes out under the car through the drains.
I test my drains regularly also, like every time it rains…