If you miss this achievement in career mode you can later replay all locations and co in Free play mode and get your missed achievements there.
Another very easy achievement. There are 6 windows (3 on each side of the truck), 2 mirrors, and the windshield.
Normally you have in this game a "window" and a "window frame" at any windows. Not with the fire truck. The black frame counts as the window-task, which makes achievement super easy. I took the yellow nozzle and went clockwise half on the window, half on the frame around the window and then the center. Window finished and simply repeat this for all windows.
For the two mirrors I go to the side of the truck and clean the mirrors from front and rear -> complete.
At the windshield don't worry about the windshield wipers they are hard to clean so no danger for achievement.