1) Figure out that you are having a problem with your foam brush.
2) Check your air gauges to see if air is getting to the solenoids. (One of my air pressure gauges were broken and other only could get to 20 psi.)
3) Check the pump to see if it is pumping. (The pump would only pump randomly. The Sandpiper pump had to build up air pressure.)
4) Open your ears and listen for an air leak. (No air leak.)
5) Check the air pressure in the air compressor. (Was fine as 100 psi.)
6) Check air pressure at the air regulator coming out of the air compressor. (My gauge was broken so I swapped it out. Then when I had a working air pressure gauge I noticed the pressure was around 20 psi.) This indicates that you should try and add more pressure output. While performing this function the knob cracked off. (It had rusted out.)
7) If knob cracks off air regulator is bad. Replace air regulator and make sure you turn the air off first. (The End)
If you have different steps let me know.