Slim pickings for us old Tucson folks.
Triple T Truck Wash closed about a year ago. They were good n cheap at $2/ft wash and dry. Give them the sad eye every time we pass by.
There is a Blue Beacon in Eloy. About 45 mi north of Tucson.
No direct knowledge, but I've heard that Prince of Tucson RV park and Voyager RV resort allow residents to wash.
Flagstaff Carwash at Grant and Silverbell has an open bay. Only one I know of on the NW side. Would take some backing and filling to position yourself. Due to hose length you'd likely have to wash one side, jockey around and do the other.
On a more positive note, monsoons should start in five or six weeks.
Fair Winds and Following Seas