Washing the car when the "dam" repair hasn't been made

I learned the hard way that there's a minor(?) defect that lets water get in to the CIU. I read all of the threads and looked at all of the pics on how to make a dam to fix the issue, but just never have the time to do it. Or the confidence, really. I mean, I'm comfortable enough with taking cars apart and (almost) putting them back together (haha), but I'm not perfectly confident in my ability to completely protect the CIU and prevent water.

In fact, shortly after going through an automatic car wash a year and a half ago, my car shut down and left me stranded on the side of the road! I was able to hobble it home, then let it sit in the garage for a month to dry out. I haven't had any major problems since, but now the backup camera only works about 25% of the time so there's apparent corrosion in the CIU :-/ So I haven't washed it in about 1 1/2 years!

The question is, how do you all safely wash your car while preventing water from getting into the CIU?