Check the fuses for anything blown. If any are, this can point you to the areas that you need to look at. Getting the computer, alternator, and battery wet tend to be problem areas for most here. Hence, why most of us do this ourselves, and normally avoid or bag those three up when washing. Check for any connections that may have been knocked loose, especially if high pressure water was used. High pressure water on engines is a bad idea. But there are a lot of videos on YouTube of people doing this, so no surprise if they did that. The high pressure can force water past seals, that can handle rain and light fording; but end up putting water in places it shouldn't be.