When I press the buttons on the pressure washer’s GFCI (Ground Fault Circuit Interrupter) plug, they don’t make clicking sounds. Why?

The GFCI plug is faulty. If your unit is under warranty, take it into the nearest Campbell Hausfeld service center. If it is not under warranty, you should take it into the nearest service center or call Campbell Hausfeld Technical Support at (800) 543-6400.