TIPS: It is recommended to skip the FAN connection, and have the fan and compressor run together through DEHU terminal. regardless of the number of units connected. If the fan stays on when the compressor goes off, a lot of that water sitting on the cold coil and drain pan has the chance to be reintroduced back into the air again right when the compressor kicks off, and give you a little RH (Relative Humidity) spike.
PS. Knob on your Quest must be turned fully counter-clockwise and make sure the switch above the knob is on "24V" (external control), not "Dehumidistat" (onboard dehumidistat).