Grand Cherokee 2WD Limited V8-4.7L (2002)
Check Valve: Description and Operation
Fig. 5 Front Check Valve
FRONT CHECK VALVE
A single front washer system check valve is standard equipment on this model, and is installed in the front washer system plumbing. The front check
valve is integral to the front washer nozzle plumbing wye fitting located in the cowl plenum area beneath the cowl plenum cover/grille panel near the
base of the windshield. The check valve consists of a molded plastic body with a raised arrowhead molded into its center section that indicates the
direction of the flow through the valve, and three barbed hose nipples formed in a wye configuration on the outside circumference of the center section
of the valve body. The front check valve cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
The front check valve provides more than one function in this application. It serves as a wye connector fitting between the cowl grille panel and
washer nozzle sections of the front washer supply hose. It prevents washer fluid from draining out of the front washer supply hoses back to the washer
reservoir. This drain-back would result in a lengthy delay when the front washer switch is actuated until washer fluid was dispensed through the front
washer nozzles, because the washer pump would have to refill the front 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.
Fig. 6 Front Check Valve
When the washer pump pressurizes and pumps washer fluid from the reservoir through the washer plumbing, the fluid pressure unseats a diaphragm
