It happened around 5:50 p.m. Wednesday.
Investigators said a black male entered the business and approached a customer. The suspect was armed with a handgun and robbed the victim.
During the robbery, the victim began to struggle with the suspect and was shot in the arm.
The victim was transported to Cape Fear Valley Medical Center and was last listed in stable condition.
Police said the suspect then fled from the car wash and ran behind Pamalee Plaza, where he approached a second victim sitting in a vehicle.
The suspect ordered the victim out of their car. That person was not injured.
Anyone with information concerning the robbery or the identity of the suspect is asked to call detectives with the Fayetteville Police Department at (910) 433-1856 or Crimestoppers at (910) 483-TIPS (8477).