2012 Jeep Wrangler JK Factory Service Manual 08 - Electrical

CHECK VALVE, Washer

FRONT

FRONT

The front check valve (2) is standard equipment on this vehicle, and is located in the engine compartment in the washer supply hose on the underside of the hood panel just outboard of the front washer nozzle. The check valve consists of a molded plastic valve body with a raised arrowhead (4) molded into its center section indicating the direction of the flow through the valve. A barbed hose nipple (1 and 3) is formed on each side of the raised center section of the valve body. Within the check valve body, a small diaphragm is held against the lip of an integral sump well by a small plastic piston and a coiled spring.

The front check valve cannot be adjusted or repaired and, if ineffective or damaged, it must be replaced.

REAR

REAR

The rear check valve (2) is located in the hardtop disconnect plate (1) located in the left inner D-pillar (3) of the removable hardtop. The disconnect plate provides a washer plumbing interconnect between the rear washer hose (4) contained within the body wire harness and the hardtop washer hose connected to the rear wiper motor. The disconnect plate also provides an electrical interconnect between the body wire harness and the hardtop wiring connected to the rear wiper motor.

The check valve consists of a molded white plastic valve body with a raised center flange and two raised wedge locks that secure the unit in the disconnect plate. A barbed outlet hose nipple is formed on the side of the valve body oriented toward the rear washer nozzle, and a straight inlet hose nipple is formed on the side of the valve body oriented toward the washer pump. Within the check valve body, a small check ball is held against an integral valve seat by a small coiled spring.

The rear check valve cannot be adjusted or repaired and, if ineffective or damaged, it must be replaced.

FRONT

FRONT

The front check valve provides more than one function in this application. 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 from when the front washer switch is actuated until washer fluid was dispensed through the front washer nozzle, because the washer pump would have to refill the front washer plumbing from the reservoir to the nozzle. 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 front check valve prevents washer fluid from siphoning out through the front washer nozzle after the front washer system is turned OFF.

When the washer pump pressurizes and pumps washer fluid from the reservoir through the front washer plumbing (5), the fluid pressure unseats a diaphragm (3) from over a sump well within the valve by overriding the pressure applied to it by a piston (2) and coiled spring (1). With the diaphragm unseated, washer fluid is allowed to flow toward the front washer nozzle (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 front washer plumbing is prevented.

REAR

REAR

The rear check valve provides more than one function in this application. It prevents washer fluid from draining out of the rear washer supply hoses back to the washer reservoir. This drain-back would result in a lengthy delay from when the rear washer switch is actuated until washer fluid was dispensed through the rear washer nozzle, because the washer pump would have to refill the rear washer plumbing from the reservoir to the nozzle. 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 rear check valve prevents washer fluid from siphoning out through the rear washer nozzle after the rear washer system is turned OFF.

When the washer pump pressurizes and pumps washer fluid from the reservoir through the rear washer plumbing, the fluid pressure unseats a check ball from a seat within the valve by overriding the pressure applied to the ball within the valve by a small coiled spring. With the check ball unseated, washer fluid is allowed to flow toward the rear washer nozzle. When the washer pump stops operating, the spring pressure on the check ball seats the ball in the valve and fluid flow in either direction within the rear washer plumbing is prevented.

FRONT

FRONT

  1. Unlatch, open and support the hood.

    2.  
  2. Locate the front check valve (4) in the washer supply hose (3) for the front washer nozzle. The check valve is installed in the washer supply hose just outboard from the front washer nozzle (2) near the rear hood panel reinforcement (1).

    3.  
  3. Disconnect the washer supply hose for the front washer nozzle from the barbed outlet nipple on the front washer system check valve. A small quantity of washer fluid may drain from the disconnected hose.

    4.  
  4. Disconnect the washer supply hose for the reservoir from the barbed inlet nipple of the front check valve. Either install a temporary plug in the washer supply hose for the reservoir or secure the loose end of this hose at a point higher than the washer reservoir to prevent the contents of the washer reservoir from draining through this hose.

    5.  
  5. Remove the front check valve from the engine compartment.

    6.  

REAR

REAR

  1. Disconnect and isolate the battery negative cable.

    2.  
  2. Unlatch and disconnect the body wire harness connector from the hardtop disconnect plate (1) connector receptacle located above the rear washer check valve (2) on the inner D-pillar (3) of the hardtop.

    3.  
  3. Disconnect the rear washer supply hose (4) from the straight inlet nipple of the rear check valve. A small quantity of washer fluid may drain from the disconnected hose.

    4.  
  4. Use a small screwdriver or a pocket knife to gently pry the latch features within each side of the disconnect plate pocket while pulling the plate away from the D-pillar.

    5.  
  5. Pull the hardtop disconnect plate away from the D-pillar far enough to access and disconnect the hardtop washer hose from the barbed outlet nipple on the back of the check valve. A small quantity of washer fluid may drain from the disconnected hose.

    6.  
  6. From the face of the disconnect plate, firmly grasp the straight nipple of the check valve and rotate it counterclockwise about 30 degrees to unlock it.

    7.  
  7. Pull the check valve straight out of the keyed opening in the disconnect plate.

    8.  

FRONT

FRONT

  1. Position the front check valve (2) in the engine compartment.

    2.  
  2. With the directional arrow (4) on the check valve pointed in the direction of the system flow, reconnect the washer supply hose from the reservoir to the barbed inlet nipple (1) of the front check valve.

    3.  
  3. Reconnect the washer supply hose from the front washer nozzle to the barbed outlet nipple (3) of the front check valve.

    4.  
  4. Check that the washer supply hoses are properly routed and are not pinched.

    5.  
  5. Close and latch the hood.

    6.  

REAR

REAR

  1. Grasp the rear check valve by the straight nipple (2).

    2.  
  2. Align the check valve with the keyed opening within the pocket of the hardtop disconnect plate (1).

    3.  
  3. Insert the check valve into the disconnect plate until the flange is firmly seated.

    4.  
  4. Rotate the check valve about 30 degrees to lock it into place.

    5.  
  5. Reconnect the hardtop washer hose from the rear washer nozzle to the barbed outlet nipple on the back of the check valve.

    6.  
  6. Align the disconnect plate with the mounting hole in the inner D-pillar (3) of the hardtop and press it firmly and evenly until it snaps back into place.

    7.  
  7. Reconnect the washer supply hose (4) from the body wire harness to the straight inlet nipple of the check valve.

    8.  
  8. Reconnect and latch the body wire harness connector to the disconnect plate connector receptacle located above the check valve.

    9.  
  9. Reconnect the battery negative cable.

    10.