A dispensing system includes a hot melt unit delivering heated adhesive through a hose to at least one dispenser gun, which is actuated by an outside source of gun actuation. Rather than directly connecting the source of gun actuation to the dispenser gun, the source of gun actuation is connected to the hot melt unit and then to the dispenser gun. For example, the gun actuation signals may be terminated at a terminal block in the hot melt unit, which enables the hot melt unit to monitor the gun actuation signals. The dispensing system is operable to perform various diagnostics pertaining to the dispenser gun and the system as a whole based on these monitored gun actuation signals.