Dakota 4WD V8-4.7L VIN J (2007)
Check Valve: Description and Operation
Operation
OPERATION
The check valve provides more than one function in this application. It serves as a wye connector fitting between the engine compartment and washer
nozzle sections of the washer supply hose. It prevents washer fluid from draining out of the washer supply hoses back to the washer reservoir. This
drain-back would result in a lengthy delay from when the washer switch is actuated until washer fluid was dispensed through the washer nozzles, because
the washer pump would have to refill the washer plumbing from the reservoir to the nozzles.
Such a drain-back condition could also result in water, dirt, or other outside contaminants being siphoned into the washer system through the washer
nozzle orifice. This water could subsequently freeze and plug the nozzle, while other contaminants could interfere with proper nozzle operation and
cause improper nozzle spray patterns. In addition, the check valve prevents washer fluid from siphoning through the washer nozzles after the washer
system is turned OFF.
When the washer pump pressurizes and pumps washer fluid from the reservoir through the washer plumbing, the fluid pressure (5) unseats a diaphragm
(3) from over a sump well within the valve by overriding the pressure applied to a piston (2) by a spring (1). With the diaphragm unseated, washer fluid
is allowed to flow toward the two washer nozzles (4). When the washer pump stops operating, the spring pressure on the piston seats the diaphragm over
the sump well in the valve and fluid flow in either direction within the washer plumbing is prevented.
