Newy...
A basic recommendation I offer all my clients with location identity challenges is to install a time & temp because it creates an instant landmark... and everyone passing uses it as a frame of reference. After a while, everyone knows where the clock is located.
Many operators with stringent sign restrictions often overlook the obvious way of identifying their site that avoids the risk of municipal oversight. Each zoning code has a definition of what constitutes a "sign". Get the definition and use it as a guide to innovate other ways of landmarking your business location.
A very familiar way is to use an illuminated flagpole with the stars & stripes conspicuously flying 24/7.
Or, simply use your building as your identifying landmark. Upgrade the landscaping... or give the structure a fresh new tastefully unique paint design. Wash the building at night with architectural lighting that highlights the facility.
Choose a picture of your carwash and include it on everything you print. Business cards, advertising, letters, tee shirts ? you're only limited by your imagination. Let everyone draw a connection with your business name... and your visual identity from the street.
There are hundreds of ways to increase your consumers' awareness of who you are and where you're located. Make a list of at least a dozen... and make it happen!