I washed my Ml320 20 mins ago and when I went to start it up the lights in the dash came on like normal and then when I tried to turn the key everything shutoff now I can even cycle the key, no lights nothing turns on. I did have the doors open while cleaning it for about 15 minutes but I don’t think that would drain the battery? Battery is close to new
Not sure if something got wet and it causing it to not turn on.

 

Check the rear taillamp gaskets for leaking. Check the rear spare tire/trunk floor area for evidence of water. W164 is known for leaking rear taillamp gaskets, causing hard to diagnose electrical problems and rear SAM failure.