PUMP-WASHER-WINDSHIELD

The washer pump/motor unit (3) is located on the outboard side of the washer reservoir, in the left front fender wheel house ahead of the front wheel and the left front wheel house splash shield. A small permanently lubricated and sealed reversible electric motor is coupled to the rotor-type washer pump (4). The use of an integral valve body (6) allows the washer pump/motor unit to provide washer fluid to either the front or the rear washer systems, depending upon the direction of the pump impeller rotation.

A seal flange with a barbed inlet nipple (8) on the pump housing passes through a rubber grommet seal installed in a dedicated mounting hole of the washer reservoir. A removable molded plastic filter screen (9) inserted into the inlet nipple prevents most debris from entering the pump housing. When the pump is installed in the reservoir the front barbed outlet nipple (5) on the pump valve body housing connects the unit to the front washer hose, and the rear barbed outlet nipple (7) connects the unit to the rear washer hose. The letters F and R molded into the valve body housing adjacent to each nipple provide further clarification of the nipple assignments.

The washer pump/motor unit is retained on the reservoir by the interference fit between the barbed pump inlet nipple and the grommet seal, which is a light press fit. The top of the washer pump is also secured to the washer reservoir by the use of a snap post (1) on the motor and a snap post receptacle molded into the reservoir that allows for mounting of the washer pump without the use of fasteners. An integral connector receptacle (2) on the top of the motor housing connects the unit to the vehicle electrical system through a dedicated take out and connector of the headlamp and dash wire harness.

The washer pump/motor unit cannot be repaired. If ineffective or damaged, the entire unit must be replaced.

OPERATION

The washer pump/motor unit features a reversible electric motor. The direction of the motor is controlled by hard wired outputs from the Front Control Module (FCM). When battery current and ground are applied to the two pump motor terminals, the motor rotates in one direction. When the polarity of these connections is reversed, the motor rotates in the opposite direction. When the pump motor is energized, the rotor-type pump pressurizes the washer fluid and forces it through one of the two pump outlet nipples, and into the front or rear washer plumbing.

The FCM controls the hard wired outputs to the pump motor based upon electronic washer request messages received over the Controller Area Network (CAN) data bus from the Steering Control Module (SCM). The SCM monitors a resistor multiplexed input from the front and rear washer switch circuitry contained within the right (wiper) multi-function switch to determine the proper washer request message to send. Whenever the low washer fluid indicator is illuminated, the FCM is programmed to suppress all rear washer requests in order to give priority to the need for forward visibility.

Washer fluid is gravity-fed from the washer reservoir to the inlet port of the washer pump housing. An integral valve body is located in a housing on the outlet port side (2) of the pump housing. A diaphragm (4) in this valve body controls which washer system plumbing receives the washer fluid being pressurized by the pump. When the pump is not operating the diaphragm is biased to close all washer fluid flow in the rear washer system and, in this way it also performs the function of the rear washer system check valve.

When the pump impeller (1) rotates in the counterclockwise direction (viewed from the bottom), the biased diaphragm is sealing off the rear washer system outlet and nipple so the pressurized washer fluid is pushed out through the pump front outlet port and the front washer outlet nipple (5). When the pump impeller rotates in the clockwise direction (viewed from the bottom), pressurized washer fluid is pushed out through the pump rear outlet port and moves the diaphragm to open the rear washer outlet nipple and seal off the front washer outlet nipple, then the pressurized washer fluid is pushed out through the rear washer outlet nipple (3).

The washer pump/motor unit and the hard wired motor control circuits from the FCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the washer pump/motor unit or the electronic controls or communication between other modules and devices that provide some features of the front and rear wiper and washer system. The most reliable, efficient, and accurate means to diagnose the washer pump/motor unit or the electronic controls and communication related to washer pump/motor unit operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

REMOVAL

NOTE: The washer pump/motor unit may be removed from the washer reservoir without removing the reservoir from the vehicle.

NOTE: Be certain to reconnect the front and rear washer hoses to the proper outlet nipples of the washer pump. Failure to properly connect the hoses will cause the front and rear washer systems to operate incorrectly.