Your issue was caused when you cleaned the engine bay with water.
Generally one of the weather pack terminals is missing a seal, allowing water to enter and short the terminals.

If you are very lucky, you will find which one, clean and dry it, and the issue will be gone.
However, electrical circuits do not like shorts, there may be secondary damage.

Here is another possible issue:
MB Wiring Harness Failure
http://www.peachparts.com/shopforum/showthread.php?p=927185