The automatic wash would not cause the faded look after only two times, but the harsh chemicals tat are used will fade them, and the rest of the plastic and rubber trim, over time (year or so).
If they looked bad after only a short time, and one wash, then perhaps the dealer used some dressing on them that dried out to look faded, or maybe even a liquid wax that would start to look lighter over a few weeks.
It also might just be as simple as them having dirt embedded in the texture of the running boards, and the automatic wash is not cleaning it out.
I know that scrubbing with the
Tire & Rubber Cleaner will make a huge improvement, and sealing them up with the
H2O Guard & Gloss will help prevent this from happening again.
Since you will also need to keep your tires clean, consider the
Tire & Rubber Cleaner Collection, which gets you the 16oz sprayer, a tire bush, and the gallon refill.
Save the Dawn Dish soap for your lasagna pan!
It is a harsh soap designed for breaking down grease, and while it might get the dirt off the running boards, it will fade them out over time.